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You searched for subject:(Modelling temperature profile). Showing records 1 – 3 of 3 total matches.

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Tampere University

1. Vuorinen, Joni. Axial fuel mixing in circulating fluidized bed boiler – measurements and modelling .

Degree: 2019, Tampere University

Efforts to decrease greenhouse gas emissions have led to growing interest in biomass usage as energy source. The circulating fluidized bed (CFB) boiler has been proven a viable option for different kinds of bio-based fuels and other challenging fuels. In addition, fluidization technologies provide a cost-effective way to reduce SOx and NOx emissions.Thus, CFB boilers can be thought as a feasible option to reduce emissions compared to some other combustion technologies. Accurate modelling can help improve the design, operation and safety of boilers, and it is seen as an important tool in the development of boilers. The goals of this thesis were to improve the accuracy of the temperature modelling in a comprehensive CFB model and to increase the knowledge on axial fuel mixing in CFB boilers. Large-scale measurements were done in a commercial CFB boiler to acquire temperature profiles when the fuels used were coal and biomass. Terminal velocities of these two different fuels were measured with and without bed material in laboratory-scale units. Image analysis was conducted for the elutriated fuel samples to obtain knowledge on size and shape of fuel particles. These measurement results were used as help when analysing the axial fuel mixing in the comprehensive CFB model. The measurements showed that bed material affects the terminal velocity of fuel particles significantly. At the solids concentrations used, it was observed that the terminal velocity of devolatilized biomass could drop to a quarter from the measurements without the bed material. The measurements without the bed material showed that the terminal velocity of biomass changes more than terminal velocity of coal, during conversion from as received to devolatilized. Based on the measurements and analysis of the comprehensive model, a new method for calculating the temperature profile was introduced in this thesis. The new method is based on a limiter for volatile combustion which allows more oxygen to go through the bottom bed and splash zone of the furnace. In addition, the fuel mixing model was manipulated so that more fuel can be elutriated to the transport zone. Results show that the modelling of the temperature profile improved with the new method. However, more research should be done relating to fuel mixing, gas mixing and biomass deformation during combustion, based on the results of this thesis.

Subjects/Keywords: Circulating fluidized bed; Modelling; Fuel mixing; Temperature profile; Terminal velocity

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Vuorinen, J. (2019). Axial fuel mixing in circulating fluidized bed boiler – measurements and modelling . (Masters Thesis). Tampere University. Retrieved from https://trepo.tuni.fi//handle/10024/116056

Chicago Manual of Style (16th Edition):

Vuorinen, Joni. “Axial fuel mixing in circulating fluidized bed boiler – measurements and modelling .” 2019. Masters Thesis, Tampere University. Accessed January 19, 2020. https://trepo.tuni.fi//handle/10024/116056.

MLA Handbook (7th Edition):

Vuorinen, Joni. “Axial fuel mixing in circulating fluidized bed boiler – measurements and modelling .” 2019. Web. 19 Jan 2020.

Vancouver:

Vuorinen J. Axial fuel mixing in circulating fluidized bed boiler – measurements and modelling . [Internet] [Masters thesis]. Tampere University; 2019. [cited 2020 Jan 19]. Available from: https://trepo.tuni.fi//handle/10024/116056.

Council of Science Editors:

Vuorinen J. Axial fuel mixing in circulating fluidized bed boiler – measurements and modelling . [Masters Thesis]. Tampere University; 2019. Available from: https://trepo.tuni.fi//handle/10024/116056


University of Alberta

2. Lecoanet, Alexandre J L. Finite Element Model of the Thermal Profile During Submerged Arc Welding with One and Two Electrodes.

Degree: MS, Department of Chemical and Materials Engineering, 2016, University of Alberta

The submerged-arc welding (SAW) process is used extensively in the manufacturing of pipes. The heat flow introduced by the welding operation has a significant impact on the properties of both the weld metal and the heat affected zone (HAZ). The work presented in this thesis aims to develop a numerical heat flow model to predict the temperature profile in piece welded using SAW as a function of the welding parameters. Measurement were done using instrumented thermocouples during an operation of SAW with one electrode. The models were then compared to the measurements and a sensitivity analysis was carried out on the density, the specific heat, the parameter called “ff” in the double ellipsoid model, and the Neumann boundary condition. The three models used are a point source model giving results similar to Rosenthal’s results, a model using a double ellipsoid heat source with constant thermal properties, and a model using a double ellipsoid heat source with varying thermal properties. The presence of the thermocouples linked to the data acquisition system used in the experiment disturbed the weld but workable data were still extracted. Then the comparison between the measurement and the simulations showed that the most accurate model is the one using a double ellipsoid heat source with varying thermal properties. It predicts well the heating and the cooling phases of all the temperature profiles recorded but it predicts the peak well only for the thermocouples located around 12 mm from the center of the plate closer it overestimates the peak. The sensitivity analysis showed that the most sensitive parameters are the thermal properties. It also showed that the parameter called “ff” in Goldak’s approach is sensitive. The Neumann boundary condition is not a sensitive parameter. Also when measurements are done using thermocouples close to the knowing the exact location of the thermocouples is crucial.

Subjects/Keywords: Submerged arc welding; SAW; Modelling of submerged arc welding; Modelling of SAW; Modelling; Finite element method; FEM; Finite element method SAW; Thermal profile; Temperature profile; Modelling temperature profile; Instrumented thermocouples; Varying thermal properties; Simulation; Simulation of SAW; Simulation of welding; FEM modelling of SAW; Quasi-steady state; Heat transfer in welding; Point source; Double ellipsoid source; Two electrode welding; Welding with two electrodes; Instrumented welds; Sensitivity of the thermal properties; Welding of X70; Welding of pipelines; Statistical analysis; Bead shape parameters; Removing outliers; Simulation of welding with COMSOL; Mixed boundary condition; Simulation with two point sources; Infinite elements; Application of infinite elements to welding; Heat tranfer in moving coordinate system; Welding; Multiple electrode welding; Sensitivity analysis; Sensitivity analysis on submerged arc welding; Sensitivity analysis on SAW; Temperature measurement during a welding operation; Temperature measurement during submerged arc welding; Temperature measurement during SAW; Modelling temperature profile during welding; Modelling temperature profile during submerged arc welding; Modelling temperature profile during SAW

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Lecoanet, A. J. L. (2016). Finite Element Model of the Thermal Profile During Submerged Arc Welding with One and Two Electrodes. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/czk51vg98f

Chicago Manual of Style (16th Edition):

Lecoanet, Alexandre J L. “Finite Element Model of the Thermal Profile During Submerged Arc Welding with One and Two Electrodes.” 2016. Masters Thesis, University of Alberta. Accessed January 19, 2020. https://era.library.ualberta.ca/files/czk51vg98f.

MLA Handbook (7th Edition):

Lecoanet, Alexandre J L. “Finite Element Model of the Thermal Profile During Submerged Arc Welding with One and Two Electrodes.” 2016. Web. 19 Jan 2020.

Vancouver:

Lecoanet AJL. Finite Element Model of the Thermal Profile During Submerged Arc Welding with One and Two Electrodes. [Internet] [Masters thesis]. University of Alberta; 2016. [cited 2020 Jan 19]. Available from: https://era.library.ualberta.ca/files/czk51vg98f.

Council of Science Editors:

Lecoanet AJL. Finite Element Model of the Thermal Profile During Submerged Arc Welding with One and Two Electrodes. [Masters Thesis]. University of Alberta; 2016. Available from: https://era.library.ualberta.ca/files/czk51vg98f

3. Lindqvist, Sandra. Vilken effekt har framtida klimat på strömningsmönster i Ekoln - en modelleringsstudie baserad på MIKE 3 FM.

Degree: LUVAL, 2019, Uppsala University

For centuries in the future, the climate on Earth will be affected by the global warming.Effects as melting ices, increasing sea levels and extreme weather, are all consequencesof the high amount of carbon dioxide (CO2), that we humans have caused. In Sweden,can climate effects like higher temperatures, longer vegetation periods and greaterseasonal variations in water fluxes, be expected. Due to climate changes and anincreasing population, the drinking water production in Uppsala will be affected. Interms of securing the drinking water production in the future, Uppsala Vatten och Avfall AB are investigating the possibility to use the Ekoln basin in lake Mälaren, as acomplementary raw water catchment area. In order to keep a secure drinking water production, in regard to quantity and quality, itis of interest to investigate how fluxes and water quality will be affected in the future.The annual pattern of water mixing, with summer- and winter stratification, and overturnduring spring and autumn, is something that significantly affects the water quality in theSwedish lakes. With the aim to study how the annual pattern of water mixing in theEkoln basin, might change due to future climate changes, hydrodynamic modelling wasperformed on a model area consisting of the Ekoln basin with adjacently bays. A hydrodynamic (3D) transport model of type MIKE 3 Flow Model FM, created byTyréns AB for simulating transport of pollutions, was calibrated and adapted to simulatetemperature profiles in the model area. To be able to study the annual pattern of watermixing, the model was also adapted to simulate a period of a year. Three scenarios weresimulated, one reference year and two future scenarios, where the future scenarios werebased on the climate scenarios RCP4.5 and RCP8.5 in year 2050. The calibration of the model was successful, and the calculation time was reduced byadapting the mesh. Results from the three scenarios, showed that the period with summerstratification might become nine days longer by RCP4.5 in year 2050, compared to thereference scenario. Simulation of RCP8.5 during the same time period, did not showany changes. By RCP8.5 it is possible that water temperatures in the epilimnion, areincreasing and that there will be no winter stratification. The temperature in the surfacewater are affected by the air temperature, in future studies it is in interest to investigatehow stratification and cirkulation will be affected by changes in wind speed and winddirection, how different types of wind data effect the results, it is also in interest to studychanges during a time period longer than one year.

Den globala uppvärmningen kommer att påverka Jordens klimat i många sekel framöver.Effekter som smältande isar, stigande havsnivåer och extremare väder, är allakonsekvenser av de enorma utsläpp koldioxid (CO2), som vi människor orsakat. ISverige kan vi i framtiden vänta oss varmare temperaturer, längre vegetationsperioderoch flöden med stora säsongsvariationer. I Uppsala kommer de…

Subjects/Keywords: Ekoln; temperature profile; hydrodynamic modelling; MIKE 3 FM; annual pattern of water mixing; climate changes; Ekoln; temperaturprofil; hydrodynamisk modellering; MIKE 3 FM; årstidsbunden cirkulation; klimatförändringar; Natural Sciences; Naturvetenskap

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Lindqvist, S. (2019). Vilken effekt har framtida klimat på strömningsmönster i Ekoln - en modelleringsstudie baserad på MIKE 3 FM. (Thesis). Uppsala University. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-390324

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):

Lindqvist, Sandra. “Vilken effekt har framtida klimat på strömningsmönster i Ekoln - en modelleringsstudie baserad på MIKE 3 FM.” 2019. Thesis, Uppsala University. Accessed January 19, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-390324.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Lindqvist, Sandra. “Vilken effekt har framtida klimat på strömningsmönster i Ekoln - en modelleringsstudie baserad på MIKE 3 FM.” 2019. Web. 19 Jan 2020.

Vancouver:

Lindqvist S. Vilken effekt har framtida klimat på strömningsmönster i Ekoln - en modelleringsstudie baserad på MIKE 3 FM. [Internet] [Thesis]. Uppsala University; 2019. [cited 2020 Jan 19]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-390324.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Lindqvist S. Vilken effekt har framtida klimat på strömningsmönster i Ekoln - en modelleringsstudie baserad på MIKE 3 FM. [Thesis]. Uppsala University; 2019. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-390324

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.