Fluid-thermal modeling of hypersonic vehicles via a gas-kinetic BGK scheme-based integrated algorithm

摘要

In our previous paper (doi: 10.1016/j.ijheatmasstransfer.2019.119016), the gas-kinetic BGK scheme was used to simulate both hypersonic flow and structural heat transfer, between which loose coupling was adopted for solving two-dimensional fluid-thermal problems. To model the unitive and continuous fluid thermal processes more actually, this paper presents a BGK scheme-based integrated algorithm and the research object is extended to three-dimensional hypersonic vehicles. To start with, an appropriate BGK model is constructed for the unified macroscopic governing equations, the effectiveness of which is verified by the Chapman-Enskog expansion analysis. Then following similar procedures in the original scheme, the gas distribution function at each cell interface is derived, from which the numerical fluxes can be evaluated. The dual-time stepping approach, together with an implicit JFNK-BGK method, is applied to efficiently obtain time-accurate solutions. With an effective parallelization strategy that is in line with the integrated algorithm, the computational efficiency is improved. As another aspect which distinguishes from the loosely-coupled methods, the fluid-structure interface conditions are also addressed. For validation, several test cases are investigated, including an individual hypersonic flow, an individual transient heat transfer, and two fluid-thermal problems. By comparison with other methods and analysis of the computed results, features of the developed method are demonstrated. (C) 2020 Elsevier Masson SAS. All rights reserved.