Thermal Modeling and Validation Testing of a Miniature Xenon Ion Thruster

• Main Author: Parker, Samuel R
• Format: Others
• Published: DigitalCommons@CalPoly 2013
• Online Access: https://digitalcommons.calpoly.edu/theses/1115; https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=2212&context=theses

To support the research of miniature ion propulsion, Cal Poly's Miniature Xenon Ion (MiXI) thruster has been modeled and tested. Using ANSYS Fluent, a two- dimensional model of the transient thermal environment of MiXI-CP-V3 was created. Validation testing was conducted in order to assess the accuracy of the thermal model. During testing, temperature was measured at eight locations across MiXI. From the test data it was determined that the thermal model did a poor job of predicting temperature due to incident radiation at the four locations nearest the keeper electrode. The four remaining locations were affected mostly by conduction and followed a trend that closely resembled the test data. The difference between the test data and the model's predicted temperature varied depending on time and location; the difference between the predicted data and the test data fell within 10C, for most of the operation but reached 27.1C at one location. The thermal model was used to assess ways to shunt heat transfer to the permanent magnets in order to postpone demagnetization, which occurs at 300C. Sheathing the entire keeper electrode with Macor was shown to reduce the temperature by as much as 13.3C at certain times and locations. Due to its lower thermal conductivity, it was hypothesized that a thruster made of titanium would impede heat transfer to the magnets, however, the model showed an increase in temperature rise when properties of certain titanium alloys are applied. Applying a thermally insulative coatings to the anode was considered, but not modeled because the available coatings have a melting point below 350C.