Through numerical simulations of the aerothermodynamics during atmospheric entry maneuvers such as re-entry, aerobraking, and aerocapture, the conditions and the incident heat flux can be approximated to support the design of the thermal protection system. Additionally, the effectiveness of aerodynamic control elements can be investigated in the rarefied gas regime.

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

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 & 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 the customer does 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 company's know-how in the numerical simulation of rarefied gas dynamics.