¶ Introduction
This page is the Design Justification File (DJF) for the diffuser, giving a quasi-homogeneous propellant flow in the HET.
¶ Definitions and Abbreviations
- DJF : Design Justification File
- HET : Hall Effect Thruster
- ERT : Epfl Rocket Team
¶ Relevant Knowledge Needed
¶ Propellant diffusion
In the Hall Effect Thruster (HET), the propellant gas must be injected in a manner that ensures uniform distribution within the discharge chamber. Additionally, the diffuser is designed to reduce the axial velocity of the propellant at the outlet, thereby increasing the residence time of the gas molecules within the electron cloud. This extended interaction time enhances the probability of ionization, contributing to improved thruster efficiency.
¶ Design Options
2 possible CAD models were rendered and adapted to the design of the HET.
Only holes are digged on the main body (tore)
Easiest to build
Rodes are helping guide the flow. It can also help reducung the velocity by friction with the walls.
Harder to build
¶ Detailed Design
The multiplication of holes allows a better dispersion of the gaz inside the chamber. The diffusive holes aligned with the input holes (where the gaz is injected) were clogged to avoid a direct flow between the gaz input and output.
Additionnal simulations should be performed to finally decide which design is best.