Improved treatment of multi-material cells in thermal radiation transport codes

• Published in: Journal of computational physics 2023-08, Vol.486, p.112116, Article 112116
• Main Authors: Till, A.T., Yessayan, R.A., Budge, K.G., Wollaeger, R.T.
• Format: Article
• Language: English
• Subjects: ALE; Arbitrary Lagrangian-Eulerian (ALE); Lagrangian-Eulerian; Multi-material closure; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; thermal radiation transport; Thermal radiation transport (TRT); TRT
• ISSN: 0021-9991; 1090-2716
• DOI: 10.1016/j.jcp.2023.112116

High-energy-density physics simulations with non-conformal meshes of materials require a multi-material (MM) closure that affects the thermal radiation transport (TRT). We propose a set of novel closures that work for an arbitrary number of materials, both grey and multigroup energy discretizations, and any angular discretization (such as Sn, IMC, or diffusion). For each spatial cell, our closures let each species (ion and electron) of each material have its own temperature, density, and internal energy, but use a single radiation distribution that interacts with all materials within the cell. Our closures maintain energy conservation, do not incur increased computational cost in the TRT solve itself, are compatible with single-material TRT solvers, and do not make any temperature-equilibrium assumptions. We test our closures on a wide range of increasingly realistic problems and find them to be robust. •Many mesh-movement strategies for hydrodynamics result in multi-material (MM) cells.•For coupled radiation-hydrodynamics, MM closures are required for the radiation.•We formulate two new MM closures for thermal radiation transport (TRT).•We assume a common radiation field that interacts with all materials within a spatial cell.•Closures are applied to implicit Monte Carlo (IMC) and discrete-ordinates transport (Sn).