Thermal Analysis of a 20-kW Class Hall Thruster

Space exploration represents one of the most difficult and inspiring challenges in the history of human progress. In the pursuit of this goal, the spacecraft propulsion system is one of the key components. High-power Hall thrusters, in particular, represent the right compromise between thrust-to-weight ratio and specific impulse, making them suitable for deep-space missions. The aim of the following thesis work is to analyse the operation of Hall thrusters and to perform a thermal analysis of the 20 kW class thruster produced by SITAEL: the HT20k. Thermal analysis was performed using the student version of the ANSYS Workbench software. An axisymmetric 2D model and a 3D model were created to compare the results of the two analyses. In particular, the impact on heat exchange of three-dimensional elements inside the thruster such as thermal straps, interfaces and radiators was investigated. The differences between the two analyses were highlighted in order to understand the actual limits of a 2D analysis for this type of thruster. A Finite Element Method (FEM) was adopted for the analysis, and it had to be supplemented with some elements of a Lumped Parameter Method (LPM) in order to make useful approximations. The thermal loads used for the analysis were input from the company but were also compared to a thermal model for calculating the internal dissipation of a Hall thruster. Finally, a transient analysis was performed under operating conditions to calculate the time required to reach a thermal steady state. The results of the analysis were promising as the various components all remained within the set operational limits. Only one component, in particular, exceeds the operating limits and a design solution was proposed to avoid this issue.