Speaker
Description
Abstract
Radiation processes are important for the description and understanding of plasma phenomena, since the radiative heat flux on the capsule can be substantial [1]. Experimental measurements are often complicated for several reasons. An alternative is the numerical simulation. Here, the common approach is the coupling of a CFD method with a radiation solver and a radiation transport solver. Especially the efficiency of these methods in dense flow regions, where radiation transfer becomes most important is an advantage. Nevertheless, the treatment of non-equilibrium effects in the flow field, which can strongly influence the radiative heat transfer, becomes problematic with CFD methods. To overcome this problem, a gas kinetic description of the plasma is necessary. This is often done by using the Direct Simulation Monte Carlo Method (DSMC) [2]. Previous approaches of coupling a particle code with a radiation solver [3, 4] revealed indeed promising results. Using DSMC, it is possible to produce detailed information about flow species, which can vary widely from the average. Detailed information about rotational, vibrational, and electronic excitation temperatures as well as the density of each species can be directly used as input variables for each cell of the radiation calculation, which would cause significant difficulties using CFD flow field data. A critical point of the radiation modeling is the solution of the Radiation Transport Equation (RTE). Here, different algorithms exist with different levels of accuracy and computational effort. In the Monte Carlo Method [5], the energy is divided into an integer number of particles. Their properties like wavelength, direction, and position are randomly assigned. The way of each beam through the cells is traced and the optical path is calculated. Subsequently, the RTE is solved in the direction of the beam. In this work, first results of solving the RTE for radiation data, which are calculated within the PIC-DSMC code PICLas, are presented.
Acknowledgement
The authors gratefully acknowledge funding provided by Airbus Defence and Space, by ArianeGroup and by the Deutsche Forschungsgemeinschaft (DFG) within the project “Partikelverfahren mit Strahlungslöser zur Simulation hochenthalper Nichtgleichgewichts-Plasmen” (project number 393159129).
References
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