稀薄气体自由分子流到连续流跨流域气动力热绕流统一算法研究  

Gas-Kinetic Unified Algorithm for Aerothermodynamics from Free-Molecular Flow to Continuum Regime

作　　者：李志辉[1,2] 彭傲平[1,2] 吴俊林[1,2] 张涵信[1,2] 

机构地区：[1]中国空气动力研究与发展中心超高速研究所,绵阳621000 [2]国家计算流体力学实验室,北京100191

出　　处：《载人航天》2013年第2期81-91,共11页Manned Spaceflight

基　　金：国家自然科学基金(91016027);国防基础科研基金(51313030104)

摘　　要：研究描述各流域气体流动输运现象统一的Boltzmann模型方程及数值求解方法,发展气体分子运动论离散速度坐标法,建立直接求解分子速度分布函数耦合迭代数值格式;研究可用于高、低不同马赫数绕流问题的Gauss型离散速度数值积分法,建立模拟各流域高超声速气动力、热绕流问题气体运动论统一算法与并行计算技术。对稀薄气体自由分子流到连续流不同Knudsen数、高低不同马赫数球体、钝锥外形、飞船返回舱再入飞行环境等绕流问题并行计算与算法验证分析,证实统一算法用于高稀薄自由分子流到连续流高超声速飞行器气动力、热绕流问题求解的可靠性,揭示飞行器跨流区不同高度高超声速绕流现象与变化规律。The unified Boltzmann model equation for gas transport phenomena of various flow regimes is presented and solved. The discrete velocity ordinate technique and the Gauss-type numerical quadrature methods are studied to resolve the barrier in simulating complex flows from low Mach numbers to hypersonic problems. Specially, the gas-kinetic finitedifference numerical scheme is constructed for the computation of three-dimensional flow problems, which directly captures the time evolution of the molecular velocity distribution function. The gas-kinetic boundary conditions and numerical procedures are studied and implemented by directly acting on the velocity distribution function. The highperformance parallel implementation technique for the gas-kinetic numerical method is developed and applied to study the hypersonic flows around three-dimensional complex bodies. The gas-kinetic unified algorithm （GKUA） solving the Bohzmann model equation is presented to study the three-dimensional hypersonic flows of spacecraft re-entry into the atmosphere. To verify the current method and simulate gas transport phenomena covering various flow regimes, the three-dimensional hypersonic flows around sphere, spherical-cone reentry and spacecraft shape with different Knudsen numbers and Mach numbers are studied. Excellent results have been obtained for all examples computed. The study indicates that the gas-kinetic unified numerical algorithm directly solving the Bohzmann simplified velocity distribution function equation may provide an important and feasible way by which complex hypersonic aerothermodynamic problems and flow mechanisms in the whole of flow regimes can be effectively studied with the aid of the power of modern computer systems.

关 键 词：BOLTZMANN模型方程 速度分布函数 离散速度坐标法 并行计算 跨流域高超 声速绕流 统一算法 航天再入飞行器 

分 类 号：V411.4[航空宇航科学与技术—航空宇航推进理论与工程] V211.25