DOI: https://doi.org/10.15368/theses.2013.197
Available at: https://digitalcommons.calpoly.edu/theses/1115
Date of Award
12-2013
Degree Name
MS in Aerospace Engineering
Department/Program
Aerospace Engineering
Advisor
Kira Abercromby
Abstract
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.