高温高速稀薄流的DSMC算法与流场传热分析

在非结构网格下,研究了热力学碰撞传能的6种方式和化学反应的8种类型,详细给出了上述碰撞传能和化学反应碰撞类型的子程序计算框图.在可变硬球(VHS)分子模型、Borgnakke-Larsen唯象模型、Bird的化学反应几率模型以及壁面CLL(Cercignani-Lampis-Lord)反射模型的基础上,用Fortran语言编制了能够模拟内能松弛、热力学非平衡和化学非平衡的稀薄气体DSMC(direct si mulation Monte-Carlo)源程序,在地球大气层和火星大气层中完成了Ballute减速装置的8个工况计算(其中Knudsen数从0.05变到30.0,飞行Mach数从26.3变到11.2),并与NASA Langley研究中心2007年发表的计算结果作了比较,本文的结果令人满意.另外,这里用|T-T_v|/T去分析热力学非平衡,用Damk hler数去分析化学反应非平衡,用Stan-ton数去分析飞行器壁面的传热效果,所有这些分析对高温部件的热防护设计十分有益. 

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.?