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University of Illinois – Urbana-Champaign
1.
Kazemifar, Farzan.
Raman-based measurements of greenhouse activity of combustion flue gases.
Degree: MS, 0133, 2011, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/26390
► Gases that are capable of absorbing and emitting infrared radiation due to their molecular structure are known as infrared active gases. Infrared activity is the…
(more)
▼ Gases that are capable of absorbing and emitting infrared radiation due to their molecular structure are known as infrared active gases. Infrared activity is the underlying reason for the greenhouse effect. Hence, greenhouse gases are all infrared active. The vibrational/rotational structure that makes the molecule infrared active, also causes the energy exchange and the corresponding wavelength shift during Raman scattering.
In this work, Raman scattering spectrum and infrared emission intensity in CO2-containing atmospheric jets at various temperatures and concentrations were measured. The results show that there is a linear relationship between Raman scattering intensity and infrared emission intensity. The linear relationship between Raman signal and infrared emission intensity indicates that Raman scattering can be used as a strong technique for measurement of greenhouse gases.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor).
Subjects/Keywords: Raman scattering; Infrared activity; Greenhouse gases; Combustion
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APA ·
Chicago ·
MLA ·
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APA (6th Edition):
Kazemifar, F. (2011). Raman-based measurements of greenhouse activity of combustion flue gases. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/26390
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Kazemifar, Farzan. “Raman-based measurements of greenhouse activity of combustion flue gases.” 2011. Thesis, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/26390.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Kazemifar, Farzan. “Raman-based measurements of greenhouse activity of combustion flue gases.” 2011. Web. 04 Mar 2021.
Vancouver:
Kazemifar F. Raman-based measurements of greenhouse activity of combustion flue gases. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2011. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/26390.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Kazemifar F. Raman-based measurements of greenhouse activity of combustion flue gases. [Thesis]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/26390
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Illinois – Urbana-Champaign
2.
Wigg, Benjamin R.
A study on the emissions of butanol using a spark ignition engine and their reduction using electrostatically assisted injection.
Degree: MS, 0133, 2011, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/24172
► Butanol is a potential alternative to ethanol and offers many benefits including a much higher heating value and lower latent heat of vaporization. It also…
(more)
▼ Butanol is a potential alternative to ethanol and offers many benefits including a much higher heating value and lower latent heat of vaporization. It also has a higher cetane number than ethanol and improved miscibility in diesel fuel. Additionally, butanol is less corrosive and less prone to water absorption than ethanol, which allows it to be transported using the existing fuel supply pipelines. However, while some previous research on the emissions of butanol-gasoline blends is available, little research exists on the emissions of neat butanol.
This thesis focuses on two areas of study. The first area relates to on the comparison of UHC, NOx, and CO emissions of several butanol-gasoline and ethanol-gasoline blended fuels during combustion in an SI engine. The objective was to compare the emissions of butanol combustion to the ones of ethanol and gasoline. The second part of the study relates to the use of electrostatically assisted injection as a means of reducing the UHC emissions of butanol by decreasing the fuel droplet size using a charge electrode and extraction ring designed for a port fuel injector. Emissions measurements taken with and without a charge applied to the injector were used to determine the effect of applying a voltage to the fuel spray on engine emissions.
It was established that the UHC emissions of neat butanol were approximately double the UHC emissions of gasoline and were appreciably higher than ethanol. CO emissions decreased and NOx emissions increased as the amount of butanol in gasoline was increased. Additionally, the CO emissions of butanol were lower than ethanol while it was not clear whether butanol had increased or decreased NOx emissions. It was also established that addition of 25% ethanol to butanol resulted in UHC emissions that were approximately 33% higher than those of neat butanol despite ethanol producing approximately 33% less UHC emissions than butanol. The results of the electrostatically assisted injection tests showed that, at certain engine operating conditions, application of 2000 V to the fuel spray resulted in a 10% increase in peak cylinder pressure, 4% reduction in UHC emissions, a 13.5% increase in NOx emissions, and a 13.5% reduction in CO emissions, which is consistent with the hypothesis that the voltage increased fuel atomization. However, tests at lower engine loads showed results contradictory to those at the higher engine load which suggested that the fuel droplet size may vary depending on engine operating conditions.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor).
Subjects/Keywords: Butanol; Electrospray; Spark Ignition (SI) Engine; Electrostatic Injection; Alternative Fuels; Fuel Spray; Fuel Injector; Ethanol
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wigg, B. R. (2011). A study on the emissions of butanol using a spark ignition engine and their reduction using electrostatically assisted injection. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/24172
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Wigg, Benjamin R. “A study on the emissions of butanol using a spark ignition engine and their reduction using electrostatically assisted injection.” 2011. Thesis, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/24172.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Wigg, Benjamin R. “A study on the emissions of butanol using a spark ignition engine and their reduction using electrostatically assisted injection.” 2011. Web. 04 Mar 2021.
Vancouver:
Wigg BR. A study on the emissions of butanol using a spark ignition engine and their reduction using electrostatically assisted injection. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2011. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/24172.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Wigg BR. A study on the emissions of butanol using a spark ignition engine and their reduction using electrostatically assisted injection. [Thesis]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/24172
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Illinois – Urbana-Champaign
3.
Evans, Christopher J.
Experimental and computational investigation of combustion phenomena in mesoscale ducts.
Degree: PhD, 0133, 2011, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/18344
► Experimental and computational investigations of the flame phenomenology in mesoscale tubes were performed. Particular emphasis was given to oscillating flames, a phenomenon in which a…
(more)
▼ Experimental and computational investigations of the flame phenomenology in mesoscale tubes were performed. Particular emphasis was given to oscillating flames, a phenomenon in which a flame front undergoes a periodic cycle of upstream propagation, extinction, and downstream re-ignition. Fuel-rich methane-oxygen mixtures and straight quartz ducts with one end open to the atmosphere were used. The flame behavior was determined as a function of equivalence ratio and Reynolds number in order to produce maps of the phenomenology and identify the boundaries between behavioral regimes. Rich propane-oxygen mixtures and multiple tube lengths were also studied in order to examine the impact of fuel selection and geometry on the regime boundaries. Infrared thermometry was utilized in order to determine the wall temperature distributions for different flame phenomenologies and to test the hypothesis that the moving nature of an oscillating flame will more uniformly distribute enthalpy throughout the duct. Both quartz and steel tubes were studied during IR experiments in order to investigate the effects of material properties on the resulting temperature distribution and flame phenomenology. Analysis of the exhaust gases was performed in order to measure fuel leakage and incomplete combustion that may occur due to the gaps in combustion that exist in the oscillation cycle. Oscillating flames were found to have fuel leakage and pollutant emission no greater than conventional stationary flames, and to produce a nearly uniform temperature in the tube wall, aspects that make them highly suitable for small-scale power generation.
The results of the experiments were used in efforts to develop a high-level computational model that could predict the flame phenomenology. The experimental results strongly suggested a thermal driving mechanism underlying oscillations and revealed the interwoven nature of the wall temperature distribution and the flame phenomenology. The computational model succeeded in qualitatively reproducing all observed flame phenomenologies. However, it was also determined that more complex mechanisms are needed in order to accurately replicate the experimentally observed boundaries between behavioral regimes.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Brewster%2C%20M.%20Quinn%22%29&pagesize-30">Brewster, M. Quinn (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Matalon%2C%20Moshe%22%29&pagesize-30">Matalon, Moshe (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Austin%2C%20Joanna%20M.%22%29&pagesize-30">Austin, Joanna M. (committee member).
Subjects/Keywords: microcombustion; oscillating flames; combustion in ducts
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Evans, C. J. (2011). Experimental and computational investigation of combustion phenomena in mesoscale ducts. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/18344
Chicago Manual of Style (16th Edition):
Evans, Christopher J. “Experimental and computational investigation of combustion phenomena in mesoscale ducts.” 2011. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/18344.
MLA Handbook (7th Edition):
Evans, Christopher J. “Experimental and computational investigation of combustion phenomena in mesoscale ducts.” 2011. Web. 04 Mar 2021.
Vancouver:
Evans CJ. Experimental and computational investigation of combustion phenomena in mesoscale ducts. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2011. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/18344.
Council of Science Editors:
Evans CJ. Experimental and computational investigation of combustion phenomena in mesoscale ducts. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/18344
4.
Lee, Sangkyoung.
Computational investigation of flahover mechanisms using fire dynamics simulator (fds).
Degree: MS, 0133, 2011, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/24363
► A pilot study of the development of flashover in enclosure fires was performed using the Fire Dynamics Simulator (FDS) platform. Practical criteria for flashover commonly…
(more)
▼ A pilot study of the development of flashover in enclosure fires was performed using the Fire Dynamics Simulator (FDS) platform. Practical criteria for flashover commonly proposed in the literature were investigated in the context of FDS modeling to determine similarity between the CFD model, previous experiments and zone-modeling results. The primary focus of the thesis was to determine FDS-generated flashover criteria that are consistent with established guidelines and can be shown to be independent of the specific configuration of the compartment. As such, a parametric study was performed to calculate the time to flashover (TTF) and maximum heat release rate as a function of parameters that relate to compartment height and ventilation configuration.
The computational domain used for this analysis was a 2.4 x 2.4 x 2.4 m3 cube with a seating chair, table and carpet with a ventilation opening centered in one wall. The results indicated that the FDS-generated flashover criteria of a radiative heat flux of 20kW/m2 at the floor level and average upper layer temperature of 600??? were, in most cases appropriate regardless of ceiling height and the configuration of ventilation. However, the results suggest that a ceiling temperature of 600 ??
C is not a good general criterion for flashover. With increasing ceiling height, the TTF increased significantly, even for a series of models that maintained a uniform compartment volume as the ceiling height increased. This latter result suggests that the delay in flashover can be attributed to the change of heat flux from the upper hot gas layer as well as the additional filling volume from a raised ceiling height. Also, modifications in ventilation size and dimension had noticeable effects on the time to flashover and maximum heat release.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor).
Subjects/Keywords: Flashover; Fire Dynamics Simulator (FDS); Ceiling Height; Ventilation
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Lee, S. (2011). Computational investigation of flahover mechanisms using fire dynamics simulator (fds). (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/24363
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Lee, Sangkyoung. “Computational investigation of flahover mechanisms using fire dynamics simulator (fds).” 2011. Thesis, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/24363.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Lee, Sangkyoung. “Computational investigation of flahover mechanisms using fire dynamics simulator (fds).” 2011. Web. 04 Mar 2021.
Vancouver:
Lee S. Computational investigation of flahover mechanisms using fire dynamics simulator (fds). [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2011. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/24363.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Lee S. Computational investigation of flahover mechanisms using fire dynamics simulator (fds). [Thesis]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/24363
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
5.
Traina, Nicholas.
Analysis of tenability, ventilation, and water application in large-scale residential fires.
Degree: MS, 0133, 2013, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/42358
► This study presents the analysis of large-scale residential fire experiments that were performed at Underwriters Laboratories in Northbrook, Illinois. These experiments were focused on the…
(more)
▼ This study presents the analysis of large-scale residential fire experiments that were performed at Underwriters Laboratories in Northbrook,
Illinois. These experiments were focused on the tenability conditions within residential fire environments and the effect of ventilation and water application on the fire environment. Experiments were conducted in one-story and two-story residential structures, with nine occurring in the one-story structure, and eight occurring in the two-story structure. Tenability conditions were determined based on CO inhalation and temperature data. In the one-story structure, CO untenability was reached, on average, 6 min. after ignition for experiments with ignition in the living room or bedrooms. In the two-story structure, CO untenability was reached, on average, 12 min. after ignition for experiments with ignition in the family room or bedrooms. In the one-story structure, CO untenability was reached prior to ventilation, which means that trapped occupants would likely be deceased in an actual fire. Times to CO untenability were drastically improved in rooms with doors shut to the fire environment, showing the importance of shutting oneself off from the fire if trapped inside a burning structure. Times to thermal untenability were typically longer than times to CO untenability, suggesting CO poisoning is more of a danger to occupants than burns. Water application was shown to improve the fire environment significantly for even small water applications. The range of duration for water applications in these experiments was 6-17 s. The correlation between duration of water application and temperature reduction inside the fire environment was not statistically significant, which suggested that the effect of water application in reducing the temperatures in the fire environment was largely due to the initial suppression of the fire in the first few seconds of water application. Temperature
iii
reduction in non-fire rooms, i.e. rooms without materials on fire, demonstrated a fairly linear relationship with the temperature before water application. It was found that this relationship was different between straight streams and fog streams. Fog streams initially have larger temperature reductions than straight stream applications, but as time reaches approximately 30 s after water application, the temperature reductions become larger for the straight stream and remain larger thereafter. Additionally, "pushing the fire" i.e. the effect of water application increasing the temperature in the rooms adjacent to the fire room, was observed only in fog streams. The reason for this "pushing the fire" effect was due to the entrainment of gases in the fog stream, which created an inflow of gases into the fire room, thus raising the pressure of the fire room and sending the hot gases into the adjacent rooms. This effect was not witnessed in straight stream applications, which was expected since entrainment of gases in the straight stream water application was negligible. A study of ventilation techniques…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor).
Subjects/Keywords: Fire; Residential; Tenability; Ventilation; Water Application; Large-Scale
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Traina, N. (2013). Analysis of tenability, ventilation, and water application in large-scale residential fires. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/42358
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Traina, Nicholas. “Analysis of tenability, ventilation, and water application in large-scale residential fires.” 2013. Thesis, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/42358.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Traina, Nicholas. “Analysis of tenability, ventilation, and water application in large-scale residential fires.” 2013. Web. 04 Mar 2021.
Vancouver:
Traina N. Analysis of tenability, ventilation, and water application in large-scale residential fires. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/42358.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Traina N. Analysis of tenability, ventilation, and water application in large-scale residential fires. [Thesis]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/42358
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
6.
Connelly, Thomas.
Experimental investigation of flame propagation in long, narrow tubes.
Degree: MS, 0133, 2013, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/44154
► Combustion of premixed propane-air flames propagating in horizontal quartz tubes of small diameter (6.4 mm) was studied using high-speed photography and Particle Streak Velocimetry (PSV).…
(more)
▼ Combustion of premixed propane-air flames propagating in horizontal quartz tubes of small diameter (6.4 mm) was studied using high-speed photography and Particle Streak Velocimetry (PSV). Several regions of propagation were established, including an initial region of uniform propagation, a subsequent region of vibratory propagation characterized by high-amplitude axial flame oscillations and acceleration of the flame, and regions of small-amplitude oscillations during which the net propagation was nearly uniform. The regions of highest instability and
acceleration were found to occur most prevalently in stoichiometric and slightly rich cases (with
fuel-air equivalence ratios of 1.0 and 1.2, respectively). The effect of tube length was also studied, using lengths of 59.1 cm and 104 cm. It was found that after a period of stable, uniform propagation, every case would inevitably transition to an unstable, oscillatory mode of
propagation, with the exception of lean mixtures in the shorter tube, in which flames propagated uniformly to the end.
Flame structure and phenomenology were also investigated. The flames in all cases began by assuming a stable, parabolic shape during uniform propagation. During regions of instability and oscillation, a large variety of flame morphologies was observed, including highly elongated shapes, partial or complete inversion of the flame front, and flames which lost a coherent shape altogether.
Finally, flow visualization was accomplished by seeding the test section with aluminum oxide (Al2O3) particles, in order to investigate the flow structures produced by the propagating flame. It was definitively established that flames propagating in tubes do produce a flow in the unburned gases ahead of the flame front. Quantitative velocity data were extracted using Particle Streak Velocimetry, which revealed that the nature of this oscillatory flow produced by the flame was unsteady and possibly 3-dimensional, defying characterization as a fully-developed laminar flow.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor).
Subjects/Keywords: Laminar flames; flame propagation in tubes; flame oscillations; particle streak velocimetry; flow visualization
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Connelly, T. (2013). Experimental investigation of flame propagation in long, narrow tubes. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/44154
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Connelly, Thomas. “Experimental investigation of flame propagation in long, narrow tubes.” 2013. Thesis, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/44154.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Connelly, Thomas. “Experimental investigation of flame propagation in long, narrow tubes.” 2013. Web. 04 Mar 2021.
Vancouver:
Connelly T. Experimental investigation of flame propagation in long, narrow tubes. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/44154.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Connelly T. Experimental investigation of flame propagation in long, narrow tubes. [Thesis]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/44154
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
7.
Rajasegar, Rajavasanth.
Experimental investigation of coal combustion in coal-laden methane jets.
Degree: MS, 0133, 2013, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/44208
► Combustion characteristics of methane jets laden with pulverized coal were studied by using a vertically oriented solid particle injector that entrained pulverized coal particles using…
(more)
▼ Combustion characteristics of methane jets laden with pulverized coal were studied by using a vertically oriented solid particle injector that entrained pulverized coal particles using the Venturi effect. The dependence of entrainment rate on the size of coal particles was studied as a function of the flow rate. Particle Streak Velocimetry performed on coal-laden jets provided valuable insight into the relative velocity of entrained coal particles with respect to the fluid velocity.
High-resolution still images and high-speed videos of laser-sheet light scattered by the coal particles helped determine the mode of interaction of entrained coal particles with the flame front. The effect of combustion on the entrained coal particles was analyzed both in terms of macrostructure and microstructure. Also, the effect of flame on coal-particle size was probed by analyzing the particle size distribution for premixed and non-premixed flames. Loose density measurements and Fraunhofer-diffraction-based particle size distribution measurements were carried out before and after combustion in order to characterize the effect of combustion on the macrostructure of coal particles. Based on the experimental results, it was established that the combustion process did not have any significant effect on the macrostructure of the coal particles. This was evidenced by the negligible changes observed in loose density and mean particle diameter after combustion.
Scanned Electron Microscopy imaging was carried out in order to study the change in microstructure of coal particles as a result of combustion. Remarkable changes were observed in microstructure while there was hardly any change in the macrostructure of coal particles due to combustion. Based on these findings, it was established that the coal particles underwent only partial devolatilization during their passage through the flame due to the small residence time. Hence it was concluded, that this mode of combustion was a surface phenomenon. The effect of oxidizer composition on the combustion of coal particles was studied by comparing the measured particle size distributions for CH4/air, CH4/O2/CO2 and CH4/O2 flames.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor).
Subjects/Keywords: pulverized coal; coal-laden methane jets; Venturi effect; Particle Streak Velocimetry
Fraunhofer diffraction; Malvern particle size measurement; Scanned Electron Microscopy; devolatilization
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Rajasegar, R. (2013). Experimental investigation of coal combustion in coal-laden methane jets. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/44208
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Rajasegar, Rajavasanth. “Experimental investigation of coal combustion in coal-laden methane jets.” 2013. Thesis, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/44208.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Rajasegar, Rajavasanth. “Experimental investigation of coal combustion in coal-laden methane jets.” 2013. Web. 04 Mar 2021.
Vancouver:
Rajasegar R. Experimental investigation of coal combustion in coal-laden methane jets. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/44208.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Rajasegar R. Experimental investigation of coal combustion in coal-laden methane jets. [Thesis]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/44208
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
8.
Schmidt, David P.
Laminar flame propagation in mixtures with compositional stratification at small length scales.
Degree: MS, 0133, 2011, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/24146
► The behavior and structure of laminar hydrocarbon flames which propagate parallel to the direction of a periodic gradient of mixture composition was studied both experimentally,…
(more)
▼ The behavior and structure of laminar hydrocarbon flames which propagate parallel to the direction of a periodic gradient of mixture composition was studied both experimentally, using a specially designed burner, and computationally, using a planar numerical model. The variations in local mixture composition led to the formation of wrinkled flames, the structure of which were dependent on both chemical and physical parameters of the particular flame configuration. A qualitative study using chemiluminescence imaging of stratified methane and propane flames was conducted to characterize their response to variations in overall mixture composition, strength and length scale of the stratification, and flow field velocity.
A two-dimensional numerical study was performed to assess the abilities of reduced global kinetic models to predict the behavior of stratified flames in comparison to computations performed using detailed mechanisms. It was observed that the reduced kinetic models display a lower limit of stratification length scale, which is on the order of the laminar flame thickness, below which accurate prediction of flame behavior is no longer possible. Under these conditions, the computed flames were observed to undergo a deformation which was much larger than the wrinkling imposed by the compositional variation, and was unsteady in time. Further analysis of these deformed flames suggested that a potential cause of this behavior was a failure of the reduced kinetics to capture the increase in local reaction rate attributed to stratification, and the inability of the driving reactions to counterbalance the incoming mass flux of fuel led to destabilization of the flame front.
A preliminary analysis of the local stretch rates of the wrinkled flames was also conducted, and it was observed that even with a uniform incoming flow field, variations in mixture composition were capable of stretching the flames. The stretch behavior observed was one of alternating flame stretch and flame compression, which reached very large magnitudes over short distances.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor).
Subjects/Keywords: Stratified Combustion; Flame Instability; Wrinkled Flame; Flame Stretch; Combustion Kinetics
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APA ·
Chicago ·
MLA ·
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APA (6th Edition):
Schmidt, D. P. (2011). Laminar flame propagation in mixtures with compositional stratification at small length scales. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/24146
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Schmidt, David P. “Laminar flame propagation in mixtures with compositional stratification at small length scales.” 2011. Thesis, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/24146.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Schmidt, David P. “Laminar flame propagation in mixtures with compositional stratification at small length scales.” 2011. Web. 04 Mar 2021.
Vancouver:
Schmidt DP. Laminar flame propagation in mixtures with compositional stratification at small length scales. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2011. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/24146.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Schmidt DP. Laminar flame propagation in mixtures with compositional stratification at small length scales. [Thesis]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/24146
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
9.
Mitsingas, Constandino.
Extinction strain rates of n-butanol, 2-butanol and iso-butanol in counterflow non-premixed flamelets.
Degree: MS, 0133, 2012, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/30996
► The extinction strain rates of three butanol isomers, (n-butanol, sec-butanol and iso-butanol) were studied experimentally in a counterflow burner, and computationally using a one-dimensional numerical…
(more)
▼ The extinction strain rates of three butanol isomers, (n-butanol, sec-butanol and iso-butanol) were studied experimentally in a counterflow burner, and computationally using a one-dimensional numerical model. The experimental results provided an insight in how the difference between molecular structures affects combustion of the isomers. Molecular branching made the isomers more prone to extinction. They shared a similar maximum temperature, as well as virtually identical high temperature kinetics, which implied that the underlying chemistry that produced difference in extinction strain rates lay, in the low-temperature oxidation steps. A numerical study was employed to calculate the extinction strain rate of n-butanol, and compare it with the experimental results. Good correlation was observed between the simulation and experimental data. During gradual increase of strain that led to extinction in the computations, the maximum temperature as well as the reaction zone thickness decreased. The mole fractions of H and OH radicals decreased, while HCO appeared to remain constant throughout the process. The formation of an annular edge flame at high strain rates was also observed experimentally for all the isomers. Very rich mixtures (ϕ=4 or higher), produced more resilient edge flames, than lean (ϕ=0.5 or lower) ones.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor).
Subjects/Keywords: butanol isomers; extinction strain rate; annular; edge flame
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Mitsingas, C. (2012). Extinction strain rates of n-butanol, 2-butanol and iso-butanol in counterflow non-premixed flamelets. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/30996
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Mitsingas, Constandino. “Extinction strain rates of n-butanol, 2-butanol and iso-butanol in counterflow non-premixed flamelets.” 2012. Thesis, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/30996.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Mitsingas, Constandino. “Extinction strain rates of n-butanol, 2-butanol and iso-butanol in counterflow non-premixed flamelets.” 2012. Web. 04 Mar 2021.
Vancouver:
Mitsingas C. Extinction strain rates of n-butanol, 2-butanol and iso-butanol in counterflow non-premixed flamelets. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/30996.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Mitsingas C. Extinction strain rates of n-butanol, 2-butanol and iso-butanol in counterflow non-premixed flamelets. [Thesis]. University of Illinois – Urbana-Champaign; 2012. Available from: http://hdl.handle.net/2142/30996
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
10.
Pennisi, Michael.
Characterization of 1-butanol electrospray combustion.
Degree: MS, 0133, 2012, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/31107
► This study examined the characteristics of electrosprays of 1-butanol that burn in air. Still images and high-speed movies captured with a laser sheet present helped…
(more)
▼ This study examined the characteristics of electrosprays of 1-butanol that burn in air. Still images and high-speed movies captured with a laser sheet present helped to establish general flame phenomenology and features such as shape, size, and stability of the spray flame. The dependence of the flame structure and stability on butanol flow rate and the applied voltage were examined. Mie-scattering-based droplet size measurements were performed in both reacting and non-reacting electrosprays. In general, a large peak in the distribution of droplet diameters centered between 40 and 50 micron was observed in the non-reacting case, with a second peak observed around 200 and 300 micron. With the flame present, a broader size distribution, still with a peak between at 40 and 50 micron, but with a larger proportion of 20 to 50 micron droplet diameters were seen. In addition, high-speed velocimetry measurements provided insight into the velocity of the droplets inside the burning spray. Some droplets were observed not to vaporize completely and pass through the flame. Photographic evidence was acquired of droplet fission in the burning spray. Charge transferred by the spray was also measured and compared with the Rayleigh limit criterion for droplet fission. An analysis of the evaporation time, based on droplet size and velocity, was used in order to rationalize the results. Indeed, large droplets traveling with velocities observed in the high speed films could pass through the flame without completely evaporating. It was concluded that the electrosprays of bio-butanol could sustain flames stabilized with the assistance of electrostatics. Furthermore, these electrospray flames had characteristics substantially different from the spray flames of non-charged fuels.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor).
Subjects/Keywords: butanol; electrospray; combustion; spray
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Pennisi, M. (2012). Characterization of 1-butanol electrospray combustion. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/31107
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Pennisi, Michael. “Characterization of 1-butanol electrospray combustion.” 2012. Thesis, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/31107.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Pennisi, Michael. “Characterization of 1-butanol electrospray combustion.” 2012. Web. 04 Mar 2021.
Vancouver:
Pennisi M. Characterization of 1-butanol electrospray combustion. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/31107.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Pennisi M. Characterization of 1-butanol electrospray combustion. [Thesis]. University of Illinois – Urbana-Champaign; 2012. Available from: http://hdl.handle.net/2142/31107
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
11.
Tse, David.
Experimental investigation of the flow field during combustion in narrow circular ducts.
Degree: MS, 0133, 2012, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/30916
► Combustion of methane-oxygen mixtures inside small diameter quartz tubes yielded cycles of ignition, flame propagation, and extinction. This phenomenon was studied with the intent of…
(more)
▼ Combustion of methane-oxygen mixtures inside small diameter quartz tubes yielded cycles of ignition, flame propagation, and extinction. This phenomenon was studied with the intent of determining the flow structure that underlay the observed oscillatory motion. The fluid motion during the oscillations was visualized by seeding TiO2 micron-sized particles. Particle Streak Velocimetry was used to obtain flow-field measurements during the oscillations. In addition, acoustic emissions from full-tube oscillations were analyzed using velocity data.
To my knowledge, the current study is the first attempt to experimentally determine the structure of these oscillatory reactive flows. It was established that the flow was essentially one-dimensional with little curving of the flow tube only near the flame front. Entropy generation from vorticity was negligible when compared with the entropy produced from combustion of methane in oxygen, as it was determined through an application of Crocco’s theorem. This confirmed previous computational studies indicating that flame oscillations are thermally, not fluid mechanically, driven. An acoustic wave propagation analysis also yielded a sound pressure level consistent with audio perception during flame oscillations with acoustic emissions.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor).
Subjects/Keywords: Flame oscillations; Combustion; Micro-combustion; Acoustic Emission; Particle Image Velocimetry; Vorticity; Crocco's theorem
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Tse, D. (2012). Experimental investigation of the flow field during combustion in narrow circular ducts. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/30916
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Tse, David. “Experimental investigation of the flow field during combustion in narrow circular ducts.” 2012. Thesis, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/30916.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Tse, David. “Experimental investigation of the flow field during combustion in narrow circular ducts.” 2012. Web. 04 Mar 2021.
Vancouver:
Tse D. Experimental investigation of the flow field during combustion in narrow circular ducts. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/30916.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Tse D. Experimental investigation of the flow field during combustion in narrow circular ducts. [Thesis]. University of Illinois – Urbana-Champaign; 2012. Available from: http://hdl.handle.net/2142/30916
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Illinois – Urbana-Champaign
12.
Kazemifar, Farzan.
An experimental study of supercritical CO2 flow in pipes and porous micro-models for carbon sequestration applications.
Degree: PhD, 0133, 2015, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/73036
► The flow of high-pressure, near-critical CO2 in configurations relevant to CO2 sequestration was investigated. The first configuration was CO2 flow in pipes and orifices at…
(more)
▼ The flow of high-pressure, near-critical CO2 in configurations relevant to CO2 sequestration was investigated. The first configuration was CO2 flow in pipes and orifices at pressures and temperatures close to the critical point of CO2 (74 bar, 31°
C). A 60-cm-long stainless steel pipe with 2.1 mm inner diameter was used in order to study near-critical CO2 pipe flow. In terms of raw flow data, the results indicated high sensitivity of pressure drop to mass flow rate as well as to inlet conditions; i.e. pressure and temperature. Remarkably though, when friction factor and Reynolds number were defined in terms of the inlet conditions, it was established that the classical Moody chart described the flow with satisfactory accuracy. This was rationalized using shadowgraphs that visualized the process of transition from a supercritical state to a two-phase subcritical state. During this transition, the two phases were separated due to density mismatch and an interface was established that traveled in the direction of the flow. This interface separated the flow in two regions of essentially single-phase flow, which explained the effective validity of the classical Moody chart. Also, Joule-Thomson throttling was studied using a 0.36-mm-diameter orifice. For conditions relevant to carbon capture and sequestration, the fluid underwent Joule-Thompson cooling of approximately 0.5°
C/bar. The temperature difference during the cooling increased with increasing inlet enthalpy. Discrepancies with previous computed and experimentally measured values of Joule-Thompson throttling were discussed in detail. In a second configuration, liquid/supercritical CO2 was injected into two-dimensional porous micro-models saturated with water, which mimicked the process of injection and flow into saline aquifers. This flow configuration was studied using fluorescent microscopy and micro-PIV by seeding the water phase with fluorescent tracer particles, and dyeing CO2 with a fluorescent dye. This technique allowed for measurement of the velocity field in the water phase, and tracking the CO2 phase in the porous medium. The results revealed the nature of the flow field during the initial invasion and migration of the CO2 front. In particular, it was established that the front developed growing dendritic features called fingers. During that growth process, velocities 20–25 times the bulk velocity were measured, which occurred in both the flow direction and opposite to it. These velocity jumps support the notion of pressure bursts and Haines jump during pore drainage events. In addition, the variations of the interfacial curvature with time and their connection with water flow field during the growth of fingers were studied. The results revealed the existence of high-momentum pathways in water ahead of growing CO2 fingers. After the passage of the CO2 front, shear-induced flow was detected in the trapped water ganglia in the form of circulation zones near the CO2-water interfaces. The shear from CO2 flow also induced motion in the thin water films…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Christensen%2C%20Kenneth%20T.%22%29&pagesize-30">Christensen, Kenneth T. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Christensen%2C%20Kenneth%20T.%22%29&pagesize-30">Christensen, Kenneth T. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Ewoldt%2C%20Randy%20H.%22%29&pagesize-30">Ewoldt, Randy H. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Valocchi%2C%20Albert%20J.%22%29&pagesize-30">Valocchi, Albert J. (committee member).
Subjects/Keywords: Carbon Sequestration; Multi-phase Flow; Porous Media; Supercritical Carbon Dioxide (CO2); Haines Jumps; Microscopic Particle Image Velocimetry (Micro-PIV); Fluorescent Microscopy
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kazemifar, F. (2015). An experimental study of supercritical CO2 flow in pipes and porous micro-models for carbon sequestration applications. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/73036
Chicago Manual of Style (16th Edition):
Kazemifar, Farzan. “An experimental study of supercritical CO2 flow in pipes and porous micro-models for carbon sequestration applications.” 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/73036.
MLA Handbook (7th Edition):
Kazemifar, Farzan. “An experimental study of supercritical CO2 flow in pipes and porous micro-models for carbon sequestration applications.” 2015. Web. 04 Mar 2021.
Vancouver:
Kazemifar F. An experimental study of supercritical CO2 flow in pipes and porous micro-models for carbon sequestration applications. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/73036.
Council of Science Editors:
Kazemifar F. An experimental study of supercritical CO2 flow in pipes and porous micro-models for carbon sequestration applications. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/73036

University of Illinois – Urbana-Champaign
13.
El Cheikh, Amne.
The effect of surface wettability on frost growth and densification on flat plates.
Degree: PhD, 0133, 2014, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/46878
► In addition to important factors like the surrounding air temperature and humidity, and surface temperature, frost growth and densification rates on cold, flat surfaces subject…
(more)
▼ In addition to important factors like the surrounding air temperature and humidity, and surface temperature, frost growth and densification rates on cold, flat surfaces subject to forced convective heat and mass transfer depend on surface wettability and cooling rate during the condensation phase. If the cooling rate is high during the condensation phase, then the droplet distribution at incipient freezing is dominated by small droplets and a narrow size range. Conversely, if the cooling rate is low during the condensation phase, then the droplet distribution at incipient freezing follows established stationary distributions with a very wide range of droplet sizes. In the present study, the impact of the surface wettability is experimentally and analytically investigated for different cooling rates in the condensation phase.
Aluminum substrates, with coatings that have undergone conversion by plasma-polymerization to alter their wettability, are used to create surfaces that range from completely wetting to hydrophobic, with advancing contact angles as high as 110o. The coated aluminum plates are then subjected to frosting conditions in wind tunnel experiments. The cooling rate during the condensation phase affects the frost thickness and density for hydrophilic and hydrophobic surfaces alike, with the low-cooling-rate condensation phase resulting in a thicker and denser frost layer—with differences exceeding 20% for thickness and density. When the frost growth is preceded by a high-cooling-rate condensation phase, the wettability effect on frost growth rate and densification is small. However, when frost growth is preceded by a low-cooling-rate condensation phase, a significantly denser frost layer grows on the hydrophilic surface. The impact of the surface wettability for a low-cooling-rate condensation phase remains significant even after 2 hours of frosting. Repeated cycles of defrost and re-frost show the same behavior.
As part of the effort to more fully understand wettability effects on frost growth, a mathematical model is developed. The coupled heat and mass diffusion equations are solved numerically, with special attention directed toward the formulation of the initial and boundary conditions, and to modeling heat and mass transport within the frost layer. Unlike previous models reported in the literature, the current formulation does not erroneously assume saturation at the frost-air interface, nor does it require specification of the super-saturation ratio. Because it is extremely difficult to measure super-saturation at the frost-air interface, prescribing it as a boundary condition vitiates the utility of the model. In the current approach, the heat flux at the frost-substrate interface is specified to close the model. This approach results in a model with much more utility and flexibility. Initial conditions for frost density and thickness are obtained from the droplet distribution on the surface during the condensation phase, providing the first link between wettability and frost growth. The model…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Jacobi%2C%20Anthony%20M.%22%29&pagesize-30">Jacobi, Anthony M. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Jacobi%2C%20Anthony%20M.%22%29&pagesize-30">Jacobi, Anthony M. (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Hrnjak%2C%20Predrag%20S.%22%29&pagesize-30">Hrnjak, Predrag S. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Wang%2C%20Xinlei%22%29&pagesize-30">Wang, Xinlei (committee member).
Subjects/Keywords: Wettability; frost; hydrophobic; hydrophilic
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
El Cheikh, A. (2014). The effect of surface wettability on frost growth and densification on flat plates. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/46878
Chicago Manual of Style (16th Edition):
El Cheikh, Amne. “The effect of surface wettability on frost growth and densification on flat plates.” 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/46878.
MLA Handbook (7th Edition):
El Cheikh, Amne. “The effect of surface wettability on frost growth and densification on flat plates.” 2014. Web. 04 Mar 2021.
Vancouver:
El Cheikh A. The effect of surface wettability on frost growth and densification on flat plates. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/46878.
Council of Science Editors:
El Cheikh A. The effect of surface wettability on frost growth and densification on flat plates. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/46878

University of Illinois – Urbana-Champaign
14.
Mejia Alvarez, Ricardo.
Experimental study of low-order models of highly-irregular roughness and their impact on turbulent boundary layers.
Degree: PhD, 0242, 2011, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/18265
► The present effort explores the relative impact of various topographical scales present within irregular surface roughness on a turbulent boundary layer under both developing- and…
(more)
▼ The present effort explores the relative impact of various topographical scales present within irregular surface roughness on a turbulent boundary layer under both developing- and developed-flow conditions. Low-order representations of highly irregular surface roughness replicated from a turbine-blade damaged by deposition of foreign materials were generated using singular value decomposition to decompose the complex topography into a set of topographical basis functions of decreasing importance to the original “full” surface character. The low-order surface models were then formed by truncating the full set of basis functions at the first 5 and 16 modes (containing approximately 71% and 95% of the full surface content, respectively) so that only the most dominant and large-scale topographical features were included in the models, while the finer-scale surface details are excluded. Physical replications of the full surface and the two low-order models were created using rapid prototyping methods to generate short and long streamwise fetches of roughness, and 2-D particle-image velocimetry (PIV) was used to acquire ensembles of instantaneous velocity fields in the streamwise–wall-normal plane for developing- and developed-flow conditions at moderate Reynolds number followed by stereo PIV measurements in a wall-parallel plane deep in the roughness sublayer (y = 0.047δ). Comparison of both single- and multipoint statistics (mean velocity and Reynolds normal and shear stresses) as well as quadrant analysis of the instantaneous events contributing to the mean Reynolds shear stress from the 2-D PIV measurements indicates that a 16-mode model of the full surface faithfully reproduces the characteristics of flow over the full surface for both developing- and developed-flow conditions. For the latter scenario, both the 5- and 16-mode models reproduce the outer-layer characteristics for flow over the full surface in accordance with Townsend’s wall similarity hypothesis. However, neither low-order surface representation fully reproduces important details of the Reynolds-shear-stress-producing events within the roughness sublayer, particularly the contributions of the most intense ejection and sweep events.
The stereo-PIV measurements deep within the roughness sublayer at y = 0.047δ reveal a wealth of information about roughness-induced effects, including the tendency of the roughness to promote ‘channeling’ of the flow in the form of low- and high-momentum pathways as noted in contour maps of the mean velocity defect. Similarly, enhanced turbulent and vortical activity is observed both between and along the spanwise
boundaries of these streamwise-elongated large-scale pathways. Taken together, these observations support the idea that these persistent low-momentum pathways might represent the statistical imprint of trains of hairpin vortex packets that are channeled along preferred paths over the roughness. Conditional averaging and two-point correlations of velocity further support these structural observations, particularly…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Christensen%2C%20Kenneth%20T.%22%29&pagesize-30">Christensen, Kenneth T. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Christensen%2C%20Kenneth%20T.%22%29&pagesize-30">Christensen, Kenneth T. (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Best%2C%20James%20L.%22%29&pagesize-30">Best, James L. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Gioia%2C%20Gustavo%22%29&pagesize-30">Gioia, Gustavo (committee member).
Subjects/Keywords: Turbulence; Boundary Layer; Rough-wall flow
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APA (6th Edition):
Mejia Alvarez, R. (2011). Experimental study of low-order models of highly-irregular roughness and their impact on turbulent boundary layers. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/18265
Chicago Manual of Style (16th Edition):
Mejia Alvarez, Ricardo. “Experimental study of low-order models of highly-irregular roughness and their impact on turbulent boundary layers.” 2011. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/18265.
MLA Handbook (7th Edition):
Mejia Alvarez, Ricardo. “Experimental study of low-order models of highly-irregular roughness and their impact on turbulent boundary layers.” 2011. Web. 04 Mar 2021.
Vancouver:
Mejia Alvarez R. Experimental study of low-order models of highly-irregular roughness and their impact on turbulent boundary layers. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2011. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/18265.
Council of Science Editors:
Mejia Alvarez R. Experimental study of low-order models of highly-irregular roughness and their impact on turbulent boundary layers. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/18265

University of Illinois – Urbana-Champaign
15.
Kim, Jihyung.
Development and experimental analysis of a micro-flame ionization detector for portable gas chromatographs.
Degree: PhD, 0133, 2014, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/46913
► A portable micro-FID has been developed that utilized a diffusion flame encased in a micro-fabricated SOI structure. The micro-flame was fueled by a portable electrolyzer…
(more)
▼ A portable micro-FID has been developed that utilized a diffusion flame encased in a micro-fabricated SOI structure. The micro-flame was fueled by a portable electrolyzer that provided the hydrogen and oxygen flow rates necessary for the device operation. The micro-FID was able to detect organic analytes with sensitivity that competes with the one of large-scale devices.
A first major accomplishment was the encasement of a stable diffusion flame inside a quartz-silicon-quartz sandwich structure. Several micro-burner configurations were tested by varying the angle between the oxidizer and the hydrogen gas of silicon channels. The final design employed a diffusion flame that was encapsulated inside a 750 µm thick silicon channel. When the streams of oxidizer and hydrogen met at a 150° angle, a single folded flame structure with low flame strain was obtained that minimized analyte loss.
The effect of channel geometry on flame structure was explored using the ANSYS FLUENT computational fluid dynamics (CFD) software package in order to compute the reactive flow in a two-dimensional geometry that simulated the micro-burner channels. Hydroxyl radical (OH) mass fraction distributions were computed as an indicator of the high-temperature zone of the flame. Also, the two-dimensional flow-field was computed in order to determine the strain rate on the non-premixed flamelet, which was used in order to rationalize flame structure. It was determined from the simulation that an angle of convergence between the channels around 150°-160° provided the least analyte loss as well as relatively low strain rates.
In order to verify this experimentally, two different channel configurations, a folded flame channel design (150° angle) and a counter-flow channel design (180° angle) were tested and compared. Methane gas was injected in the hydrogen stream and the resulting ion current was measured. The folded flame channel design produced about 34 times stronger signals compared to the counter-flow channel design. The micro-FID that was based on this configuration had a linear response.
In order to improve signal strength and reduce fuel consumption rate, an oxygen stream was added to the air stream and the overall channel width size was reduced to 50%. Additionally, reducing the dead volume of the injection port and introducing anchor points to the channels improved the overall device performance. These modifications allowed reducing the overall fuel consumption and improved the sensitivity by a factor of about three. In order to increase the sensitivity of the device, not only was the signal strength improved, but also efforts were made to reduce the noise. To this end, channels were fabricated with silicon-on-insulator wafers and the entire micro-FID was tested inside a Faraday cage. These modifications suppressed the noise by a factor of 43 and improved the overall sensitivity and the minimum detection level. Furthermore, it enabled the instrument to detect a mixture of 17 different gas compounds.
The fuel flow rate…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Shannon%2C%20Mark%20A.%22%29&pagesize-30">Shannon, Mark A. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Shannon%2C%20Mark%20A.%22%29&pagesize-30">Shannon, Mark A. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Scheeline%2C%20Alexander%22%29&pagesize-30">Scheeline, Alexander (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Ferreira%2C%20Placid%20M.%22%29&pagesize-30">Ferreira, Placid M. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22King%2C%20William%20P.%22%29&pagesize-30">King, William P. (committee member).
Subjects/Keywords: micro-combustion
flame ionization detector
(micro-FID)
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kim, J. (2014). Development and experimental analysis of a micro-flame ionization detector for portable gas chromatographs. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/46913
Chicago Manual of Style (16th Edition):
Kim, Jihyung. “Development and experimental analysis of a micro-flame ionization detector for portable gas chromatographs.” 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/46913.
MLA Handbook (7th Edition):
Kim, Jihyung. “Development and experimental analysis of a micro-flame ionization detector for portable gas chromatographs.” 2014. Web. 04 Mar 2021.
Vancouver:
Kim J. Development and experimental analysis of a micro-flame ionization detector for portable gas chromatographs. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/46913.
Council of Science Editors:
Kim J. Development and experimental analysis of a micro-flame ionization detector for portable gas chromatographs. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/46913

University of Illinois – Urbana-Champaign
16.
Peuker, Steffen.
Experimental and analytical investigation of refrigerant and lubricant migration.
Degree: PhD, 0133, 2011, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/18284
► The off-cycle refrigerant mass migration has a direct influence on the on-cycle performance since compressor energy is necessary to redistribute the refrigerant mass. No studies,…
(more)
▼ The off-cycle refrigerant mass migration has a direct influence on the on-cycle performance since compressor energy is necessary to redistribute the refrigerant mass. No studies, as of today, are available in the open literature which experimentally measured the lubricant migration within a refrigeration system during cycling or stop/start transients. Therefore, experimental procedures measuring the refrigerant and lubricant migration through the major components of a refrigeration system during stop/start transients were developed and implemented. Results identifying the underlying physics are presented.
The refrigerant and lubricant migration of an R134a automotive A/
C system-utilizing a fixed orifice tube, minichannel condenser, plate and fin evaporator, U-tube type accumulator and fixed displacement compressor-was measured across five sections divided by ball valves. Using the Quick-Closing Valve Technique (QCVT) combined with the Remove and Weigh Technique (RWT) using liquid nitrogen as the condensing agent resulted in a measurement uncertainty of 0.4 percent regarding the total refrigerant mass in the system. The determination of the lubricant mass distribution was achieved by employing three different techniques-Remove and Weigh, Mix and Sample, and Flushing. To employ the Mix and Sample Technique a device-called the Mix and Sample Device-was built. A method to separate the refrigerant and lubricant was developed with an accuracy-after separation-of 0.04 grams of refrigerant left in the lubricant. When applying the three techniques, the total amount of lubricant mass in the system was determined to within two percent. The combination of measurement results-infrared photography and high speed and real time videography-provide unprecedented insight into the mechanisms of refrigerant and lubricant migration during stop-start operation.
During the compressor stop period, the primary refrigerant mass migration is caused by, and follows, the diminishing pressure difference across the expansion device. The secondary refrigerant migration is caused by a pressure gradient as a result of thermal nonequilibrium within the system and causes only vapor phase refrigerant migration. Lubricant migration is proportional to the refrigerant mass during the primary refrigerant mass migration. During the secondary refrigerant mass migration lubricant is not migrating.
The start-up refrigerant mass migration is caused by an imbalance of the refrigerant mass flow rates across the compressor and expansion device. The higher compressor refrigerant mass flow rate was a result of the entrainment of foam into the U-tube of the accumulator. The lubricant mass migration during the start-up was not proportional to the refrigerant mass migration.
The presence of water condensate on the evaporator affected the refrigerant mass migration during the compressor stop period. Caused by an evaporative cooling effect the evaporator held 56 percent of the total refrigerant mass in the system after three minutes of compressor stop…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Hrnjak%2C%20Predrag%20S.%22%29&pagesize-30">Hrnjak, Predrag S. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Hrnjak%2C%20Predrag%20S.%22%29&pagesize-30">Hrnjak, Predrag S. (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Bullard%2C%20Clark%20W.%22%29&pagesize-30">Bullard, Clark W. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Jones%2C%20Barclay%20G.%22%29&pagesize-30">Jones, Barclay G. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Newell%2C%20Ty%20A.%22%29&pagesize-30">Newell, Ty A. (committee member).
Subjects/Keywords: refrigerant; Lubricant; oil; migration; R134a; automotive; experimental techniques; air conditioning; transient; cycling; refrigerant mass distribution; lubricant mass distribution; Quick Closing Valve Technique; mechanisms of refrigerant and lubricant migration
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Peuker, S. (2011). Experimental and analytical investigation of refrigerant and lubricant migration. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/18284
Chicago Manual of Style (16th Edition):
Peuker, Steffen. “Experimental and analytical investigation of refrigerant and lubricant migration.” 2011. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/18284.
MLA Handbook (7th Edition):
Peuker, Steffen. “Experimental and analytical investigation of refrigerant and lubricant migration.” 2011. Web. 04 Mar 2021.
Vancouver:
Peuker S. Experimental and analytical investigation of refrigerant and lubricant migration. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2011. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/18284.
Council of Science Editors:
Peuker S. Experimental and analytical investigation of refrigerant and lubricant migration. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/18284

University of Illinois – Urbana-Champaign
17.
Cheng, Way Lee.
A numerical study of the multi-component effects on the combustion and evaporation of biofuels and blends.
Degree: PhD, 0133, 2011, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/18375
► Biodiesel fuels and their blends with diesel are often used to reduce carbon trace and to help reducing engine emissions. However, previous studies have shown…
(more)
▼ Biodiesel fuels and their blends with diesel are often used to reduce carbon trace
and to help reducing engine emissions. However, previous studies have shown mixed
effects of biodiesel on NOx emissions. Operating a compression-ignition engine in low-
temperature combustion mode as well as using multiple injections can reduce NOx
emissions. The effects of injection timing, spray angle and fuel composition are studied
using a modified version of KIVA 3V code. The objectives of this research include: 1) to
examine the effects of fuel on engine performance and emissions; 2) to study the effects
of spray angle on flow patterns and pollutants formation using a discrete multi-
component approach; 3) to develop a new droplet evaporation model using the
continuous thermodynamics formulation, which is capable in accommodating multiple
distribution functions, accounts for preferential evaporation, finite diffusion and surface
regression of the droplet; 4) to demonstrate the applicability of the proposed model in
engine applications. A numerical study is also conducted to study the effect of spray
angle in a small bore high speed direct injection engine. Soot located in the squish region
or the region above the piston bowl are readily oxidized due to abundance of oxygen.
Portions of fuel are burnt in the region about the piston bowl or squish for both spray
angles of 150?? and 70??. Soot located within the piston bowl is oxidized at a much slower
rate due to deficient of oxygen after combustion. Soot emissions are mainly due to soot
remaining within in the piston bowl at the end of combustion cycle. Any strategy that
pushes soot out of the piston bowl can improve the oxidation process, thus, reducing soot
emission. Extra oxygen in biodiesel also helps in reducing the emission. The effects of variable cone angle spray on the performance of a diesel engine are studied. Using a
variable cone angle injection extends the range of injection time without engine wall
wetting, which decreases soot and unburnt hydrocarbon emissions. The numerical
predictions show a 10% improvement in thermal efficiency without compromising NOx
and soot emissions.
The study shows that the evaporation of the fuel affects the ignition behavior and
combustion quality. Therefore, a thorough understanding of the evaporation and mixing
processes is essential for further improvement in engine performance. A multi-
component droplet evaporation model, as efficient as a traditional zero-dimensional
model, yet preserving the correct description of the underlying physical process is
developed in this study. The continuous thermodynamics formulation is used, for which
the fuel (or liquid mixture) is described using a probability distribution function. The
variation of composition in both liquid and vapor phases is represented by tracing the
changes of the probability distribution function parameters. In the present study, the
gamma distribution is used to represent the fuel…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Lee%2C%20Chia-Fon%22%29&pagesize-30">Lee, Chia-Fon (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Lee%2C%20Chia-Fon%22%29&pagesize-30">Lee, Chia-Fon (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Vanka%2C%20Surya%20Pratap%22%29&pagesize-30">Vanka, Surya Pratap (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Hansen%2C%20Alan%20C.%22%29&pagesize-30">Hansen, Alan C. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (committee member).
Subjects/Keywords: Biofuels; Multi-component; Continuous Thermodynamics; Droplet Evaporation; Variable cone angle spray
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Cheng, W. L. (2011). A numerical study of the multi-component effects on the combustion and evaporation of biofuels and blends. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/18375
Chicago Manual of Style (16th Edition):
Cheng, Way Lee. “A numerical study of the multi-component effects on the combustion and evaporation of biofuels and blends.” 2011. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/18375.
MLA Handbook (7th Edition):
Cheng, Way Lee. “A numerical study of the multi-component effects on the combustion and evaporation of biofuels and blends.” 2011. Web. 04 Mar 2021.
Vancouver:
Cheng WL. A numerical study of the multi-component effects on the combustion and evaporation of biofuels and blends. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2011. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/18375.
Council of Science Editors:
Cheng WL. A numerical study of the multi-component effects on the combustion and evaporation of biofuels and blends. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/18375
18.
Agathou, Maria.
Bio-butanol fuel atomization and combustion processes.
Degree: PhD, 0133, 2010, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/16709
► Three bio-butanol fuel atomization and combustion technologies were considered, namely butanol electrostatic sprays, butanol non-premixed flames, and butanol kinetic modeling in view of the emergence…
(more)
▼ Three bio-butanol fuel atomization and combustion technologies were considered, namely butanol electrostatic sprays, butanol non-premixed flames, and butanol kinetic modeling in view of the emergence of methods of production of this fuel from biological sources.
Butanol electrospray (e-spray) phenomenology was investigated through high-speed visualization and compared with the corresponding electrosprays of ethanol, heptane and butanol-containing mixtures. Electrospray structure was probed using Phase Doppler Anemometry and both droplet size and velocity measurements were obtained for sprays of butanol and butanol-containing fuel blends. These results indicated an unstable and polydisperse electrospray behavior for most conditions. Several factors were identified as responsible for this unstable behavior and were investigated experimentally. These included: e-spray menisci oscillations, instabilities initiating the droplet break-up, secondary droplet break-up because of high Weber numbers and finally stability of butanol electrical conductivity with applied voltage. Stable butanol electrosprays were achieved within a narrow region of low flow rates and a non-dimensional analysis was performed in order to develop an empirical expression correlating the dimensionless average diameter, flow rate and applied voltage.
Butanol non-premixed flames were studied in a counter-flow burner configuration. Major combustion species were measured using line Raman imaging and K-type thermocouples were used in order to perform temperature scans across the flame. Also, extinction strain rates were measured as a function of overall stoichiometry. Butanol flames were compared with flames of methane (which is not oxygenated) as well as ethanol which is a currently widely employed biofuel and with butanol-methane mixture flames. It was shown that butanol flames could sustain higher strain rates at extinction than ethanol flames but significantly smaller than methane flames. For the strongly diluted flames under consideration, it was shown that temperature followed a very closely linear relation with nitrogen concentration. For the same nitrogen concentration, butanol exhibited lower temperatures at the same overall stoichiometry and heat release, because of the higher average molecular weight of the fuel stream. In addition, the possibility of estimating the scalar dissipation rate at the stoichiometric surface χstoich was investigated through a measurement of the mixing layer thickness. It was proven that approximating the mixing layer thickness through the gradient of the mixture fraction at the stoichiometric surface, offered a good estimation of χstoich.
Butanol kinetic modeling was studied in a zero-dimensional piston-cylinder assembly and a MATLAB code was used in order to solve the energy conservation and species equations. Pressure and temperature results were provided as a function of time, along with mol fractions of major species and combustion intermediates. The same calculation was performed for ethanol and n-heptane.…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">
Kyritsis,
Dimitrios C. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Brewster%2C%20M.%20Quinn%22%29&pagesize-30">Brewster, M. Quinn (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Lee%2C%20Chia-Fon%22%29&pagesize-30">Lee, Chia-Fon (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Hansen%2C%20Alan%20C.%22%29&pagesize-30">Hansen, Alan C. (committee member).
Subjects/Keywords: bio-butanol; atomization; electrosprays; combustion; diffusion flames; Raman spectroscopy; kinetic modeling
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Agathou, M. (2010). Bio-butanol fuel atomization and combustion processes. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/16709
Chicago Manual of Style (16th Edition):
Agathou, Maria. “Bio-butanol fuel atomization and combustion processes.” 2010. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/16709.
MLA Handbook (7th Edition):
Agathou, Maria. “Bio-butanol fuel atomization and combustion processes.” 2010. Web. 04 Mar 2021.
Vancouver:
Agathou M. Bio-butanol fuel atomization and combustion processes. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2010. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/16709.
Council of Science Editors:
Agathou M. Bio-butanol fuel atomization and combustion processes. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2010. Available from: http://hdl.handle.net/2142/16709
19.
Huo, Ming.
Air/fuel mixing enhancement and emission reduction through intake port design and various fuel emulsions for diesel combustion.
Degree: PhD, 0133, 2015, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/72925
► Upcoming environmental constraints require the next generation internal combustion engine (ICE) to yield lower pollutant emissions and higher fuel efficiency. The air/fuel mixture inside the…
(more)
▼ Upcoming environmental constraints require the next generation internal combustion engine (ICE) to yield lower pollutant emissions and higher fuel efficiency. The air/fuel mixture inside the ICE, which has a pivotal impact on the subsequent combustion and emission performance, is a key aspect to achieve those requirements. The work done in this dissertation aims at exploring different strategies to enhance the air/fuel mixing rates and thus to improve the combustion and reduce emission in the modern ICE.
The air/fuel mixing enhancement can be approached from both sides of the mixture. For air, different intake port designs were considered to generate a strong in-cylinder tangential velocity, known as swirl flow, to promote air/fuel mixing. The mean and turbulent characteristics of the swirl flow were explored under various valve lifts using particle image velocimetry (PIV). This information is of significant value for advanced combustion strategies such as reactivity controlled compression ignition (RCCI) in which the fuel stratification before autoigntion is critical for combustion efficiency. Furthermore, the correlation between the PIV and conventional bench flow measurement using paddle wheel swirl meter, which is of particular importance in guiding the future industrial bench flow tests, was also demonstrated.
For fuel, although the spray and atomization process could be improved through complicated hardware design, the atomization enhancement due to inherent fuel properties is more attractive due to its low cost and easy implementation. In this study, water as an additive was mainly considered for enhancing spray atomization and air/fuel mixing through a unique behavior known as micro-explosion. Although the micro-explosion phenomena in fuel droplets have been extensively studied, their presence in the fuel spray and the corresponding impact on the combustion and emissions has rarely been reported. In this work, various laser diagnostic methods were applied to capture the spray and combustion characteristics of fuels with additives and as such, the observed phenomena were correlated with other combustion features. The findings will be important towards the fundamental understanding of the spray and combustion of these multi-component fuels under diesel-engine-like conditions and valuable for future computational model validation.
Through this work, a) Swirl flow generated through different intake ports were demonstrated using PIV measurement and the potential mixing enhancement using certain port design was shown; b) The impacts of in-cylinder velocity flow field, piston geometry and injection timing on fuel stratification were demonstrated through a simulation study.
c) High speed imaging was carried out in a constant volume chamber to reveal the spray and combustion processes of diesel fuel with various additives under various ambient conditions. Quantitative analysis of spray penetration, soot lift-off length, broadband natural flame luminosity and soot distribution were performed. d) It is revealed…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Lee%2C%20Chia-Fon%22%29&pagesize-30">Lee, Chia-Fon (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Lee%2C%20Chia-Fon%22%29&pagesize-30">Lee, Chia-Fon (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Christensen%2C%20Kenneth%20T.%22%29&pagesize-30">Christensen, Kenneth T. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Austin%2C%20Joanna%22%29&pagesize-30">Austin, Joanna (committee member).
Subjects/Keywords: air/fuel mixing; intake flow; emulsions
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Huo, M. (2015). Air/fuel mixing enhancement and emission reduction through intake port design and various fuel emulsions for diesel combustion. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/72925
Chicago Manual of Style (16th Edition):
Huo, Ming. “Air/fuel mixing enhancement and emission reduction through intake port design and various fuel emulsions for diesel combustion.” 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/72925.
MLA Handbook (7th Edition):
Huo, Ming. “Air/fuel mixing enhancement and emission reduction through intake port design and various fuel emulsions for diesel combustion.” 2015. Web. 04 Mar 2021.
Vancouver:
Huo M. Air/fuel mixing enhancement and emission reduction through intake port design and various fuel emulsions for diesel combustion. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/72925.
Council of Science Editors:
Huo M. Air/fuel mixing enhancement and emission reduction through intake port design and various fuel emulsions for diesel combustion. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/72925
20.
Peuker, Jennifer.
Using optical techniques to measure aluminum burning in post-detonation explosive fireballs.
Degree: PhD, 0133, 2012, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/30968
► Metals are added to high explosives and propellants to increase the heat of explosion. Aluminum is commonly used because it has a high energy density,…
(more)
▼ Metals are added to high explosives and propellants to increase the heat of explosion. Aluminum is commonly used because it has a high energy density, is relatively inexpensive, is easy to produce, and has a low toxicity. To optimize the performance and safety of aluminized explosives, it is necessary to understand where, when, and with what the aluminum is reacting in the explosive fireball. Efforts in aluminum combustion have focused on aluminum monoxide (AlO) emission because it is easy to measure, and it is a combustion marker in some cases; however, the first part of the current study has indicated that explosive fireballs are optically thick. Therefore, external measurements are biased toward conditions near the fireball surface. The objectives of the current study are twofold: (1) to further the understanding of aluminum combustion in an explosive fireball, specifically where, when, and with what the aluminum is reacting; and (2) to characterize AlO emission measurements from aluminized explosive fireballs in order to determine when and how AlO emission can be used as an indicator of aluminum combustion.
Experiments were completed in six different environments–air, pure O2, pure CO2, pure N2, 40%/60% O2/N2 and 20%/80% CO2/N2–using four distinct aluminized charges of varying aluminum particle size–3, 10, and 40 micron–and loading amount–20 and 50 percent–by mass, to determine with what the aluminum is reacting. In addition, a charge containing 20 percent aluminum oxide was used as an inert comparison. Contrasting results from optical–emission spectroscopy, pyrometry and high speed imaging–and non-optical techniques–recovered residue analysis and overpressure measurements–is used to challenge typical interpretations of optical measurements of aluminized explosive fireballs. The effect of the aluminum particle location with respect to the explosive material was tested by using end-loaded charges, and by placing a layer of grease on the aluminized charge tip. Time-resolved overpressure measurements are used to determine when the aluminum is burning. Experiments employing an air-gap between the explosive charge and aluminum powder aid in determining how and when aluminum is activated and combusted in the initial blast wave and the subsequent fireball containing high pressure and high temperature detonation products.
Tests in four environments–air, pure O2, pure CO2, and pure N2–show that even when AlO emission intensity is lower by 90 percent in N2 or CO2 than it is in air for a charge, it is possible to have significant–60 to 70 percent–aluminum particle oxidation. In addition, substantial AlO emission was measured in the absence of unburned aluminum–almost half of the peak AlO emission measured when unburned aluminum was present. Results show that AlO emission intensity measurements are skewed to higher AlO intensities by high transient temperatures within the first 30 microseconds when the peak AlO emission is usually measured. The aluminum particle location also affects the amount of AlO emission…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Glumac%2C%20Nick%20G.%22%29&pagesize-30">Glumac, Nick G. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Glumac%2C%20Nick%20G.%22%29&pagesize-30">Glumac, Nick G. (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Krier%2C%20Herman%22%29&pagesize-30">Krier, Herman (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Austin%2C%20Joanna%20M.%22%29&pagesize-30">Austin, Joanna M. (committee member).
Subjects/Keywords: Aluminum; Combustion; Explosive Fireball; Optical Measurements
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
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APA (6th Edition):
Peuker, J. (2012). Using optical techniques to measure aluminum burning in post-detonation explosive fireballs. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/30968
Chicago Manual of Style (16th Edition):
Peuker, Jennifer. “Using optical techniques to measure aluminum burning in post-detonation explosive fireballs.” 2012. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/30968.
MLA Handbook (7th Edition):
Peuker, Jennifer. “Using optical techniques to measure aluminum burning in post-detonation explosive fireballs.” 2012. Web. 04 Mar 2021.
Vancouver:
Peuker J. Using optical techniques to measure aluminum burning in post-detonation explosive fireballs. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/30968.
Council of Science Editors:
Peuker J. Using optical techniques to measure aluminum burning in post-detonation explosive fireballs. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2012. Available from: http://hdl.handle.net/2142/30968
21.
Jain, Neera.
Thermodynamics-based optimization and control of integrated energy systems.
Degree: PhD, 0133, 2013, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/44250
► With increasing worldwide demand for energy comes the need to both generate and consume energy more efficiently. Integrated energy systems (IESs) combine power generation technologies,…
(more)
▼ With increasing worldwide demand for energy comes the need to both generate and consume energy more efficiently. Integrated energy systems (IESs) combine power generation technologies, such as internal combustion engines or fuel cells, with other technologies which directly utilize the power produced by the generator and/or utilize the thermal energy otherwise wasted in the production of power. IESs are becoming more prevalent because of their environmental, economic, and reliability benefits. However, to fully realize these benefits, effective optimization and control of IESs is required. In turn, this requires a function which can accurately capture the objectives (performance, efficiency, etc.) for the system in terms of desired decision variables.
The aim of this research is to develop a systematic methodology for developing objective functions to be used in conjunction with optimal control algorithms for improving operational efficiency and performance of IESs. This is accomplished through the use of a thermodynamics-based minimization metric, exergy destruction, which is used as the foundation for deriving objective functions which are 1) physics-based, 2) generalizable to a wide class of IESs, and 3) modular with the ability to characterize not only an entire IES but also specific subsystems of a larger IES. Exergy destruction can be used to characterize irreversibilities across multiple energy domains (chemical, electrical, mechanical, and thermal) making it a particularly suitable metric for IESs.
The generalizability and modularity of the optimization framework is demonstrated through static setpoint optimization of a combined heating, cooling, and power (CCHP) system with time-varying performance demands. It was shown that minimizing exergy destruction increases exergetic efficiency at some expense of energy consumption, but that the decrease in exergy destruction can possibly outweigh the increases in energy consumption. An additional layer of flexibility was introduced as the “interchangeability” between power minimization and exergy destruction rate minimization for those subsystems in which the reversible power is constant with respect to the decision variables. Interchangeability allows the user to only derive the exergy destruction rate for those systems in which the equivalence does not hold and construct an objective function which would result in the same solution as minimizing the rate of exergy destruction in every subsystem.
Exergy analyses have long been used to better understand the behavior of a variety of thermodynamic systems, primarily from a static design and operation point of view. However, as the complexity of integrated energy systems grows, for example as a result of intermittent grid power from renewable energy technologies such as wind and solar, an understanding of transient behavior is needed. As a case study, the dynamic exergy destruction rate was derived for the refrigerant-side dynamics of a vapor-compression cycle system and then used in formulating an exergy…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Alleyne%2C%20Andrew%20G.%22%29&pagesize-30">Alleyne, Andrew G. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Alleyne%2C%20Andrew%20G.%22%29&pagesize-30">Alleyne, Andrew G. (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Salapaka%2C%20Srinivasa%20M.%22%29&pagesize-30">Salapaka, Srinivasa M. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Dom%C3%83%C2%ADnguez-Garc%C3%83%C2%ADa%2C%20Alejandro%20D.%22%29&pagesize-30">Domínguez-García, Alejandro D. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Stoustrup%2C%20Jakob%22%29&pagesize-30">Stoustrup, Jakob (committee member).
Subjects/Keywords: optimization and control; thermal energy systems; second-law analysis; exergy analysis; integrated energy systems
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Jain, N. (2013). Thermodynamics-based optimization and control of integrated energy systems. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/44250
Chicago Manual of Style (16th Edition):
Jain, Neera. “Thermodynamics-based optimization and control of integrated energy systems.” 2013. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/44250.
MLA Handbook (7th Edition):
Jain, Neera. “Thermodynamics-based optimization and control of integrated energy systems.” 2013. Web. 04 Mar 2021.
Vancouver:
Jain N. Thermodynamics-based optimization and control of integrated energy systems. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/44250.
Council of Science Editors:
Jain N. Thermodynamics-based optimization and control of integrated energy systems. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/44250

University of Illinois – Urbana-Champaign
22.
Mullen, Jessica C.
Composite propellant combustion with low aluminum agglomeration.
Degree: PhD, 0133, 2010, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/16047
► Aluminum behavior—accumulation, agglomeration and ignition—is studied in a unique, wide-distribution, ammonium perchlorate/hydroxyl-terminated polybutadiene (AP/HTPB) propellant formulation that results in low Al agglomeration, even at low…
(more)
▼ Aluminum behavior—accumulation, agglomeration and ignition—is studied in a unique, wide-distribution, ammonium perchlorate/hydroxyl-terminated polybutadiene (AP/HTPB) propellant formulation that results in low Al agglomeration, even at low pressures (1-30 atm). Variations in formulation—such as fine-AP/binder ratio, Al particle size, Al loading, coarse-AP size—are also examined. A fuel-rich, oxygenated binder matrix highly loaded with fine (2-µm) AP (FAP) at 75/25:FAP/binder (by mass) is found to have premixed flame conditions that produce minimal agglomeration (without ignition) of 15-µm Al. Coarse AP (CAP) is added to the system in the form of either particles (200 or 400 µm) or pressed-AP laminates (simulated CAP). In the 2-D laminate system the CAP/oxyfuel-matrix flame structure is seen to be similar to that previously described for non-aluminized laminates with split (diffusion) and merged (partially-premixed) flame regimes, depending on pressure and fuel-matrix thickness. Both laminate and particulate systems show that with CAP present, Al can agglomerate more extensively on CAP via lateral surface migration from fuel matrix to the CAP region. The particulate CAP system also shows that Al can accumulate/agglomerate via settling on CAP from above (in the direction of burning). Both systems, but more clearly the 2-D laminates, show that with CAP present, Al is ignited by the outer CAP/fuel-matrix canopy flames. Thus, a propellant formulation is proposed for reducing overall Al agglomeration through intrinsically reduced agglomeration in the fuel-matrix and a reduced number of CAP-particle agglomerates via higher FAP/CAP ratio.
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Brewster%2C%20M.%20Quinn%22%29&pagesize-30">Brewster, M. Quinn (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Brewster%2C%20M.%20Quinn%22%29&pagesize-30">Brewster, M. Quinn (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Jacobi%2C%20Anthony%20M.%22%29&pagesize-30">Jacobi, Anthony M. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Austin%2C%20Joanna%20M.%22%29&pagesize-30">Austin, Joanna M. (committee member).
Subjects/Keywords: Aluminum; Low Agglomeration; Hydroxyl-terminated Polybutadiene
(HTPB); Wide-distribution AP; Fine-AP particles (FAP); ammonium perchlorate/hydroxyl-terminated polybutadiene (AP/HTPB) flames; Laminate; Ammonium Perchlorate (AP)
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Mullen, J. C. (2010). Composite propellant combustion with low aluminum agglomeration. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/16047
Chicago Manual of Style (16th Edition):
Mullen, Jessica C. “Composite propellant combustion with low aluminum agglomeration.” 2010. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/16047.
MLA Handbook (7th Edition):
Mullen, Jessica C. “Composite propellant combustion with low aluminum agglomeration.” 2010. Web. 04 Mar 2021.
Vancouver:
Mullen JC. Composite propellant combustion with low aluminum agglomeration. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2010. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/16047.
Council of Science Editors:
Mullen JC. Composite propellant combustion with low aluminum agglomeration. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2010. Available from: http://hdl.handle.net/2142/16047

University of Illinois – Urbana-Champaign
23.
Kiyanda, Charles B.
Detonation modelling of non-ideal high explosives.
Degree: PhD, 0242, 2010, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/16069
► High explosives (HE) are used in many fields where the energy liberated by the combustion process is used to perform useful work. High explosives normally…
(more)
▼ High explosives (HE) are used in many fields where the energy liberated by the combustion process is used to perform useful work. High explosives normally burn via a detonation; a supersonic wave consisting of a shock wave coupled to chemical energy release. Detonations in conventional HE (CHE) propagate with a typical velocity of 6 - 8 km/s. Insensitive HE (IHE) and non-ideal HE (NIHE) are of particular interest as they are
harder to initiate and thus safer to store and transport. Detonations in IHEs and NIHEs are characterized by longer reaction time and length scales than detonations in CHE. NIHEs are typically characterized by their porous, granular structure. Detonations in NIHEs have lower detonation velocities (4 - 6 km/s) than those in CHEs or IHEs due to their lower initial densities.
The short time scales (O(ns ??? ??s)), length scales (O(??m ??? mm)) and the opaque nature of HEs and their products make experimental observations, required to calibrate detonation models for reaction flow modelling, challenging. Currently used reactive burn models assume a two component, mechanically equilibrated mixture of reactants and products. Individual components are modelled with an empirical equation of state (EOS). The set of relations which uniquely determine the mixture-averaged state in terms of the states of the mixture constituents, the mixture closure conditions, are also often of a pressure-temperature equilibrium form. The chemical reaction rate law(s) are mostly based on preconceptions of how a detonating HE burns.
Typically, such engineering style models are complex and contain a large number of fitting parameters that are calibrated in some form to a limited set of experimental data. Minimal attention has been devoted to the physical and mathematical implications of the fitting process and reactive burn model structure (such as the choice of closure condition) to issues such as detonation stability and interacting oblique shock structure. For a well-posed reactive burn model, such properties should be understood.
A majority of this thesis research is devoted to formulating and studying the shock and detonation properties of reactive burn models based on the use of stiffened-gas (SG) equations of state. A SG model allows
an appropriate initial sound speed of a material to be set, an important improvement over ideal gas models when applied to condensed phase reactive burn models. Due to its relative simplicity, a semi-analytical understanding of reactive burn models based on the use of SG EOS models for its constituent components can be obtained. Furthermore, changes in physical aspects of the reactive burn model, such as detonation
stability and interacting oblique shock structure, with changes in calibrated fitting parameters, can be better understood. In this context, we establish the ability of SG EOS models to reasonably formulate a reactive burn model for the IHE PBX 9502. The model is designed to capture the fast and slow reaction stages inherent in PBX 9502 detonation using a two-stage…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Short%2C%20Mark%22%29&pagesize-30">Short, Mark (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Short%2C%20Mark%22%29&pagesize-30">Short, Mark (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Austin%2C%20Joanna%20M.%22%29&pagesize-30">Austin, Joanna M. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Pantano-Rubino%2C%20Carlos%20A.%22%29&pagesize-30">Pantano-Rubino, Carlos A. (committee member).
Subjects/Keywords: detonation; detonation modelling; high explosive; condensed explosive; PBX 9502; insensitive; Ammonium nitrate-fuel oil (ANFO); equation of state; stiffened-gas; Empirical equation of state (EOS)
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kiyanda, C. B. (2010). Detonation modelling of non-ideal high explosives. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/16069
Chicago Manual of Style (16th Edition):
Kiyanda, Charles B. “Detonation modelling of non-ideal high explosives.” 2010. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/16069.
MLA Handbook (7th Edition):
Kiyanda, Charles B. “Detonation modelling of non-ideal high explosives.” 2010. Web. 04 Mar 2021.
Vancouver:
Kiyanda CB. Detonation modelling of non-ideal high explosives. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2010. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/16069.
Council of Science Editors:
Kiyanda CB. Detonation modelling of non-ideal high explosives. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2010. Available from: http://hdl.handle.net/2142/16069

University of Illinois – Urbana-Champaign
24.
Lynch, Patrick T.
High temperature spectroscopic measurements of aluminum combustion in a heterogeneous shock tube.
Degree: PhD, 0133, 2010, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/17022
► Aluminum is an important energetic material that burns with a variety of oxidizers with a high reaction enthalpy. It is a top performer for energy…
(more)
▼ Aluminum is an important energetic material that burns with a variety of oxidizers with a high reaction enthalpy. It is a top performer for energy density if oxidizer mass is considered as well as the fuel. Because of this, it is often used as an energetic additive in anaerobic conditions because it reacts in what typically are products of primary fuels and oxidizers and further increases chamber temperatures in solid rocket motors or blast overpressure in enhanced blast weapons. Despite decades of research, gaps still exist in the knowledge of how aluminum burns, especially with the recent trend of using smaller particles (10 micron and below). While aluminum is a very energetic material, its rate of oxidation is relatively low, and efforts are made to not only increase the heat release rate of particles reacting with oxidizer, but also to increase peak combustion temperature. Experimental studies were performed measuring the combustion characteristics of aluminum in the heterogeneous shock tube. The heterogeneous shock tube provides unmatched control of temperature, pressure, oxidizer concentration, etc., in which to test energetic materials of different particle sizes.
The burning time diameter exponent, n as in t_b ~ d^n, in aluminum particle combustion was measured to be as low as, or lower than 0.3, in conditions in the transition regime between kinetic and diffusion limited particles. This anomalous result, as well as observed increases of burn time with pressure when using water vapor as an oxidizer had been attributed to a pressure dependence on ignition of particles in these conditions or broad overlapping size distributions. Both theories were tested and rejected.
Furthermore, an acrylic end section was implemented on the shock tube which provides complete optical access to the final 61 cm of the shock tube. This optical access allowed high speed images (50k fps) of the particle motion, ignition, and combustion. Results are presented which give a more complete understanding of burntime variability in the heterogeneous shock tube, owing to the contribution of initially wall-bound particles vs. those that are in the free stream upon the passage of the incident shock, bright clusters of rapidly moving burning particles, and non-uniform cloud distributions in the tube, all previously undifferentiated by shock tube burntime methods.
Absorption spectroscopy was used to probe the ground state of Aluminum monoxide (AlO), a gas phase combustion intermediate, and Al vapor in order to quantify the amount of Al and AlO present under conditions where these species were not observed in emission previously, notably in most conditions with nano-aluminum particles. At least three regimes of combustion were observed for nano-aluminum combustion. At temperatures above 2000 K, particles burn with AlO and Al vapor present. Between 1500 K and 2000 K, particles burn with Al vapor present, but without detectable AlO. Between 1200 K and 1500 K, particles burn without either vapor phase component present. These…
Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Glumac%2C%20Nick%20G.%22%29&pagesize-30">Glumac, Nick G. (advisor),
Champaign%22%20%2Bcontributor%3A%28%22Glumac%2C%20Nick%20G.%22%29&pagesize-30">Glumac, Nick G. (Committee Chair),
Champaign%22%20%2Bcontributor%3A%28%22Krier%2C%20Herman%22%29&pagesize-30">Krier, Herman (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Kyritsis%2C%20Dimitrios%20C.%22%29&pagesize-30">Kyritsis, Dimitrios C. (committee member),
Champaign%22%20%2Bcontributor%3A%28%22Scheeline%2C%20Alexander%22%29&pagesize-30">Scheeline, Alexander (committee member).
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Lynch, P. T. (2010). High temperature spectroscopic measurements of aluminum combustion in a heterogeneous shock tube. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/17022
Chicago Manual of Style (16th Edition):
Lynch, Patrick T. “High temperature spectroscopic measurements of aluminum combustion in a heterogeneous shock tube.” 2010. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021.
http://hdl.handle.net/2142/17022.
MLA Handbook (7th Edition):
Lynch, Patrick T. “High temperature spectroscopic measurements of aluminum combustion in a heterogeneous shock tube.” 2010. Web. 04 Mar 2021.
Vancouver:
Lynch PT. High temperature spectroscopic measurements of aluminum combustion in a heterogeneous shock tube. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2010. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2142/17022.
Council of Science Editors:
Lynch PT. High temperature spectroscopic measurements of aluminum combustion in a heterogeneous shock tube. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2010. Available from: http://hdl.handle.net/2142/17022
.