Particle method coupled with a radiation transport solver for the simulation of high-enthalpy, non-equilibrium plasma

在项目提案中，将开发一种新的微观方法，将基于粒子的数值流体动力学与流场辐射传输求解器相结合。因此，将首次有可能对在强热和化学非平衡状态下的辐射等离子体流进行详细的数值研究，例如在航天器重返大气层期间、在电力推进系统中以及在涉及等离子体的其他一些具有挑战性的应用中。以前的方法通过将传统的计算流体动力学（CFD）与辐射输运求解器耦合来解决这个问题。然而，这些方法不适用于非平衡流的连续性假设打破。此外，由于离散的能级，原子和分子的内部自由度（旋转、振动和/或电子激发）的建模仅在使用CFD方法进行几次简化后才可行。然而，这些分子特性的处理对于辐射的物理精确建模是必不可少的。将通过与实验数据（隼鸟号和星尘号再入）进行比较，对新开发的耦合方法以及辐射输运方程的有效解进行验证和确认。可以预期的是，测量的辐射光谱可以更准确地再现由于高保真度的内部自由度内的流的物理建模，使在等离子体流的实验测量和效果的基本理解。

Within the project proposal, a novel microscopic method coupling particle-based numerical fluid dynamics with a radiation transport solver for the flow field shall be developed. Consequently, detailed numerical investigations of radiating plasma flows in strong thermal and chemical non-equilibrium will be possible for the first time such as during the re-entry of spacecraft, in electric propulsion systems and several other challenging applications involving plasma. Previous approaches tackle this subject by coupling conventional computational fluid dynamics (CFD) with a radiation transport solver. However, these methods are not applicable for non-equilibrium flows as the continuum assumption breaks down. Additionally, the modeling of internal degrees of freedom of atoms and molecules (rotational, vibrational and/or electronic excitation) is only feasible with several simplifications with CFD methods due to discrete energy levels. The treatment of these molecular properties though is essential for a physically-accurate modeling of radiation. The newly developed methods for the coupling as well as the efficient solution of the radiation transport equation shall be verified and validated by comparison to experimental data (Hayabusa and Stardust re-entry). It is expected that the measured radiation spectra can be reproduced more accurately due to the high-fidelity physical modeling of the internal degrees of freedom within the flow, enabling an underlying understanding of the experimental measurements and effects in the plasma flows.