Validation of grid current simulations using the particle-in-cell method for a miniaturized ion thruster
Abstract
The numerical simulation of ion thruster optics is one of the most common applications of particle-based methods in the field of electric propulsion. Over the years, powerful tools for simulation of ion trajectories and charge exchange erosion have been developed and validated. However, not fully conservative physical models have to be applied with caution, since they are likely to fail when a kinetic modeling of both ions and electrons is relevant, which is mostly the case when electron fluid models (e.g., the Boltzmann relation) lose their validity, such as in the simulation of ion beam neutralization. For this, a more sophisticated approach based on high fidelity Particle-In-Cell (PIC) methods is expected to be necessary. Highly parallel computation concepts are required to attain feasible simulation times also for more complex geometries. Recently, the ion thruster operation at electron back-streaming limit was simulated using the efficient hybridizable discontinuous Galerkin Poisson solver of the 3D PIC-DSMC code PICLas. The shown accordance between fully kinetic simulations and those using the common Boltzmann relation (BR) justifies to focus for validation and sensitivity analyses on BR cases. Therefore, new optics simulations for a RIT-μX EBB thruster of Airbus are performed. Experimental validation is achieved by comparing simulated grid currents at several operating conditions. Parameter studies show the influence of plasma parameters and collision models for charge exchange. For a scattering-based collision model, good quantitative agreement is achieved for a reasonable assumption of neutral gas temperature. Also the erosion pattern from experiments is reproduced qualitatively.
- Publication:
-
31st International Symposium on Rarefied Gas Dynamics: RGD31
- Pub Date:
- August 2019
- DOI:
- 10.1063/1.5119534
- Bibcode:
- 2019AIPC.2132d0003B