SKM 2021 – scientific programme

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VA: Fachverband Vakuumphysik und Vakuumtechnik

VA 1: Rarefied gas flows and novel approaches for particle simulation

VA 1.2: Invited Talk

Monday, September 27, 2021, 10:30–11:00, H2

Deterministic modeling of neutral gas flows of tokamak nuclear fusion devices — •Christos Tantos and Stylianos Varoutis — Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany

Over the last few years much effort has been invested in modeling transport phenomena appearing in the complex geometry of the divertor region in tokamak fusion devices. Depending on the upstream plasma conditions, the flow reference Knudsen number, defined as the ratio of the mean free path over a characteristic length, may vary over a wide range. The rarefied flow behavior in these systems cannot be properly captured by the typical Navier-Stokes-Fourier approach and must be described by the integro-differential Boltzmann equation or reliable kinetic model equations. The Discrete Velocity Method (DVM) has developed into one of the most common techniques for solving the Boltzmann equation and the kinetic models. As it is well known simulating multidimensional rarefied gas problems based on the Boltzmann equation is computationally time consuming. Therefore, successful implementation of reliable kinetic models in such problems is important. In the present work, the Boltzmann equation is approximated by the well-known Bhatnagar Gross Krook (BGK) and Shakhov kinetic models supplemented with the deterministic discrete velocity method. Results are presented for He and D2 covering a wide range of the involved parameters. Extended comparisons between the deterministic approach and the stochastic Direct Simulation Monte Carlo (DSMC) method are presented.