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，将基于颗粒的数值流体动力学与流场的辐射输运求解器耦合起来。因此，在强热和化学非平衡状态下对辐射等离子体流进行详细的数值研究将首次成为可能，例如在航天器再入过程中，在电力推进系统和其他一些涉及等离子体的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）与辐射输运求解器相结合来解决这个问题。然而，这些方法不适用于非平衡流动，因为连续介质假设已经失效。此外，原子和分子的内部自由度（旋转、振动和/或电子激发）的建模由于能级离散，只能通过CFD方法的若干简化来实现。然而，对这些分子特性的处理对于辐射的物理精确建模至关重要。新开发的耦合方法和辐射输运方程的有效解将通过与实验数据（隼鸟号和星尘号再入）的对比进行验证和验证。由于对流动内部自由度的高保真物理建模，可以更准确地再现测量的辐射光谱，从而能够对等离子体流动中的实验测量和影响有一个潜在的理解。

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.