The numerical simulation of cold gas thrusters and electric propulsion systems can be utilized to predict and to optimize the performance of the thrusters. Additionally, the impact of the expanding plume on surrounding systems (e.g., solar arrays or other mission critical components) or the plume-plume interaction can be approximated through simulation.

For this purpose, boltzplatz utilizes the open-source software PICLas, which combines multiple particle-based solvers such as the Particle-in-Cell (PIC), Direct Simulation Monte Carlo (DSMC) and Bhatnagar-Gross-Krook (BGK) methods for the simulation of rarefied gas and plasma flows.

The Particle-in-Cell (PIC) method self-consistently models a collisionless flow of charged particles under the influence of electromagnetic forces. To treat electromagnetic or electrostatic interaction, Maxwell’s or Poisson’s equations are solved with a high-order discontinuous Galerkin solver:

• Stand-alone 3D simulations or coupled with other particle-based methods such as DSMC
• Efficient and scalable parallelization concept optimized for high-performance computing
• Choice between electromagnetic or electrostatic treatment depending on the application

The Direct Simulation Monte Carlo (DSMC) method in PICLas for the simulation of non-equilibrium, high-enthalpy rarefied gas flows has a multitude of features including:

• 1D, 2D, axisymmetric (including a radial weighting) and 3D simulations
• Mesh independence with the on-the-fly octree-based mesh refinement and a nearest neighbor algorithm
• Broad range of available species from electrons to polyatomic molecules such as methane and carbon-dioxide
• Treatment of chemical reactions and ionization processes using the Arrhenius-based Total Collision Energy (TCE) model, the threshold-based Quantum-Kinetic (QK) model or the cross-section-based Monte Carlo Collision (MCC) model

The Bhatnagar-Gross-Krook (BGK) approximation allows the efficient simulation of denser gas flows, where the DSMC method becomes computationally expensive. While the particle-based method in PICLas is continuously extended, key features have already been implemented:

• 2D, axisymmetric (including a radial weighting), and 3D simulations
• Single species simulations with diatomic and polyatomic molecules using quantized vibrational energy treatment
• Simulation of gas mixtures with the multi-species modeling for atomic and diatomic species

boltzplatz offers numerical simulations as a service, where customers do not have to worry about the simulation setup and computational resources, but can benefit from the simulation results. If customers would like to perform the simulations on their premises, boltzplatz can provide support along the complete tool chain with the compayn's know-how in the numerical simulation of rarefied plasma dynamics.