Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for subject:(electric satellite propulsion). Showing records 1 – 2 of 2 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


Michigan Technological University

1. Jackson, Brandon. Meniscus Modeling and Emission Studies of an Ionic Liquid Ferrofluid Electrospray Source Emitting from a Magneto-Electric Instability.

Degree: PhD, Department of Mechanical Engineering-Engineering Mechanics, 2018, Michigan Technological University

This dissertation presents three studies on the electrospray of ionic liquid ferrofluid. Ionic liquid ferrofluids are electrically conductive super-paramagnetic fluids which respond strongly in the presence of electric and magnetic fields. When a small reservoir of ionic liquid ferrofluid is positioned within a magnetic field, magnetic stresses will deform the fluid interface into a peak. The addition of a strong electric field will further stress the fluid interface until a threshold stress is reached at which point the surface tension cannot contain the combined stresses and a spray of fluid or ions results at the apex. This process is termed electrospray, albeit a less understood form of electrospray owing to the addition of magnetic stresses which are not present in traditional electrospray. The first study included in this dissertation presents a computational fluid dynamics model of the combined electro-magnetic instability critical for electrospray. The developed model utilized the static formulation of the Maxwell equations to calculate the Maxwell stress tensor for an ionic liquid ferrofluid. When combined with the Stokes stress tensor, the duo of equations capture the fluid stresses present within the instability. The model was first employed to study the influence of a magnetic field on the onset potential of a capillary needle electrospray source. The simulation predicted onset potential agreed well with the experimentally captured onset under matching field conditions. The numerical tool was then utilized to study the dynamics of sessile ionic liquid ferrofluid droplets. The computational results were verified against laboratory images of sessile drops obtained under matching field conditions. The simulation performed exceptionally up until about 85% of the onset potential at which point the simulation began to over predict the apex height of the combined instability. The second portion of this dissertation consisted of long duration emission studies of an ionic liquid ferrofluid normal-field source. An operational procedure was developed which permitted a source consisting of a single emitter to operate with constant extraction potential for spans in extent of 15 hours. Time-lapse imagery of source enabled the mass flow rate to be approximated, permitting derived propulsion performance parameters to be obtained. Three different magnetic field strengths were investigated, and it was found that the magnetic field strength has no identifiable impact on propulsion performance. On average, the mass flow rate of the source was 28 ng/s (15.5 pL/s), with a specific impulse of 1385 s and a thrust of 0.380 µN per emitter. During the telemetry, the sensitivity of the source was analyzed and it was found that for moderate changes in extraction potential the source remained stable, but for increases on the order of 25-30% of the baseline voltage secondary emission sites were observed to form. The final set of studies included in this dissertation focuses investigated the angular divergence of… Advisors/Committee Members: Lyon King.

Subjects/Keywords: ferrofluid; electrospray; ionic liquid; electric satellite propulsion; ferromagnetisim; Other Mechanical Engineering; Propulsion and Power

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Jackson, B. (2018). Meniscus Modeling and Emission Studies of an Ionic Liquid Ferrofluid Electrospray Source Emitting from a Magneto-Electric Instability. (Doctoral Dissertation). Michigan Technological University. Retrieved from http://digitalcommons.mtu.edu/etdr/587

Chicago Manual of Style (16th Edition):

Jackson, Brandon. “Meniscus Modeling and Emission Studies of an Ionic Liquid Ferrofluid Electrospray Source Emitting from a Magneto-Electric Instability.” 2018. Doctoral Dissertation, Michigan Technological University. Accessed January 19, 2020. http://digitalcommons.mtu.edu/etdr/587.

MLA Handbook (7th Edition):

Jackson, Brandon. “Meniscus Modeling and Emission Studies of an Ionic Liquid Ferrofluid Electrospray Source Emitting from a Magneto-Electric Instability.” 2018. Web. 19 Jan 2020.

Vancouver:

Jackson B. Meniscus Modeling and Emission Studies of an Ionic Liquid Ferrofluid Electrospray Source Emitting from a Magneto-Electric Instability. [Internet] [Doctoral dissertation]. Michigan Technological University; 2018. [cited 2020 Jan 19]. Available from: http://digitalcommons.mtu.edu/etdr/587.

Council of Science Editors:

Jackson B. Meniscus Modeling and Emission Studies of an Ionic Liquid Ferrofluid Electrospray Source Emitting from a Magneto-Electric Instability. [Doctoral Dissertation]. Michigan Technological University; 2018. Available from: http://digitalcommons.mtu.edu/etdr/587

2. Sanborn, Graham Patrick. A thin film triode type carbon nanotube field electron emission cathode.

Degree: PhD, Materials Science and Engineering, 2013, Georgia Tech

The current technological age is embodied by a constant push for increased performance and efficiency of electronic devices. This push is particularly observable for technologies that comprise free electron sources, which are used in various technologies including electronic displays, x-ray sources, telecommunication equipment, and spacecraft propulsion. Performance of these systems can be increased by reducing weight and power consumption, but is often limited by a bulky electron source with a high energy demand. Carbon nanotubes (CNTs) show favorable properties for field electron emission (FE) and performance as electron sources. This dissertation details the developments of a uniquely designed Spindt type CNT field emission array (CFEA), from initial concept to working prototype, to specifically prevent electrical shorting of the gate. The CFEA is patent pending in the United States. Process development enabled fabrication of a CFEA with a yield of up to 82%. Furthermore, a novel oxygen plasma etch process was developed to reverse shorting after CNT synthesis. CFEA testing demonstrates FE with a current density of up to 293 μA/cm² at the anode and 1.68 mA/cm² at the gate, with lifetimes in excess of 100 hours. A detailed analysis of eighty tested CFEAs revealed three distinct types of damage. Surprisingly, about half of the damaged chips are not electrically shorted, indicating that the CFEAs are very robust. Potential applications of this technology as cathodes for spacecraft electric propulsion were explored. Exposure to an operating electric propulsion thruster showed no significant effect or damage to the CFEAs, marking the first experimental study of CNT field emitters in an electric propulsion environment. A second effort in spacecraft propulsion is a collaboration with the Air Force Institute of Technology (AFIT). CFEAs are the payload on an AFIT developed Cube Satellite, called ALICE, to test electron emission in the space environment. ALICE has passed flight tests and is awaiting launch scheduled for 5 December 2013. Advisors/Committee Members: Ready, W. Jud (advisor), Wong, C. P. (advisor), Walker, Mitchell (committee member), Yushin, Gleb (committee member), Teo, Ken (committee member).

Subjects/Keywords: Carbon nanotube; Field emission; Electron emission; Spindt; Triode; Electric propulsion; Hall effect thruster; Cube satellite; Carbon nanotubes; Field emission cathodes

…HPEPL High Power Electric Propulsion Laboratory I Current IAD Ion assisted deposition… …of electric propulsion for spacecraft that normally use inefficient hot cathodes to ionize… …abilities for CNT electron sources. Ideal applications include spacecraft electric propulsion… …For example, a 200-W Hall effect thruster for satellite propulsion requires 1 A of emission… …Field eV Electron volts Ex Kinetic energy of electrons F Electric field xxii f(E… 

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Sanborn, G. P. (2013). A thin film triode type carbon nanotube field electron emission cathode. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/50302

Chicago Manual of Style (16th Edition):

Sanborn, Graham Patrick. “A thin film triode type carbon nanotube field electron emission cathode.” 2013. Doctoral Dissertation, Georgia Tech. Accessed January 19, 2020. http://hdl.handle.net/1853/50302.

MLA Handbook (7th Edition):

Sanborn, Graham Patrick. “A thin film triode type carbon nanotube field electron emission cathode.” 2013. Web. 19 Jan 2020.

Vancouver:

Sanborn GP. A thin film triode type carbon nanotube field electron emission cathode. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2020 Jan 19]. Available from: http://hdl.handle.net/1853/50302.

Council of Science Editors:

Sanborn GP. A thin film triode type carbon nanotube field electron emission cathode. [Doctoral Dissertation]. Georgia Tech; 2013. Available from: http://hdl.handle.net/1853/50302

.