DSMC algorithm and heat transfer analysis of high temperature and high velocity rarefied gas flow

This paper studied 6 kinds of energy transfer of thermodynamic collision and 8 types of chemical reaction on unstructured grids.Subroutine flow charts of the energy transfer and chemical reaction collision mentioned above were proposed in detail.Based on variable hard sphere(VHS) model,Borgnakke-Larsen phenomenological model,chemical reaction model of Bird and Cercignani-Lampis-Lord(CLL) gas surface interaction model,a rarefied gas direct simulation Monte-Carlo(DSMC) code was produced using Fortran,enabling to simulate relaxation of internal energies,thermodynamic nonequilibrium and chemical reaction nonequilibrium.The computation of towed ballute applications of 8 cases was completed in the Earth's and Mars' atmosphere,in which Knudsen number changes from 0.05 to 30.0,flight Mach number changes from 26.3 to 11.2.The results were compared with the computation published by James N.Moss from NASA Langley Research Center in 2007,showing satisfactory agreement.In addition,this paper analyzed thermodynamic nonequilibrium,chemical reaction nonequilibrium and heat transfer efficiency of vehicle wall,by using |T-T_v|/T,Damkhler number and Stanton number,respectively.The analysis is beneficial to thermal protection design of high temperature assemblies.