Modeling of Hall thruster lifetime and erosion mechanisms

Hall thrusters and other types of electric propulsion have become a tempting alternative to traditional chemical propulsion systems for in-space applications due to the high specific impulses (Isp) they provide. Large Isp translates to a highly desirable mass savings and system trades show that Hall thrusters fall in an optimum operation regime well suited for missions such as station-keeping and orbit transfers. However, uncertainty about thruster lifetime has impeded the device's widespread integration as mission designers want a propulsion system guaranteed to last the entire mission duration. Furthermore, recent interest in applying the technology to more complex propulsion tasks has suggested that throttle-capable thrusters will become desirable and concern about the effect of operating condition on thruster longevity has been raised. To aid in early design stages and later thruster qualification, development of a computational life-prediction tool is needed since experimental lifetime testing is prohibitively expensive and time-consuming. In this work, an axisymmetric hybrid-PIC model, HPHall, has been upgraded to simulate the erosion of the Hall thruster acceleration channel, the degradation of which is the main life-limiting factor of the propulsion system. Evolution of the thruster geometry as a result of material removal due to sputtering is modeled by calculating wall erosion rates, stepping the grid boundary by a chosen time step and altering the computational mesh between simulation runs. The code is first tuned to predict the nose cone erosion of a 200W Busek Hall thruster, the BHT-200. Simulated erosion profiles from the first 500 hours of operation compare favorably to experimental data.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Cheng, Shannon Yun-Ming, 1978-

Advisor dc:contributor.advisor

• Manuel Martinez-Sanchez.

• Aeronautics and Astronautics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/42043

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/42043