The unified Boltzmann model equation is presented for describing three-dimensional complex hypersonic flow transport phenomena covering various flow regimes by modeling processing of Boltzmann collision integral.The gas-kinetic numerical schemes of coupling iteration are constructed directly to capture and update the time evolution of the molecular velocity distribution function by using explicit operator splitter,and then the mathematical model of high-performance parallel computation is presented by the surroundings of massive parallel programmer for the Gas-Kinetic Unified Algorithm (GKUA)in solving the Boltzmann model equation.The computing principle of domain decomposition is investigated on the basis of two-phase six-dimensional space of physical space and velocity space,the data-communication expression of the domain decomposition strategy is deduced for the gas-kinetic numerical method,and then the computing technique of parallel domain decomposition in the discrete velocity space is presented.As a result,the gas-kinetic massive parallel algorithm is developed to solve the hypersonic aerothermodynamics from rarefied transition to continuum covering various flow regimes.Based on the parallel program testing and the numerical parallel experiment with different CPU scales of 256—512,4096—20 625 and numbers of processor cores 500—45 000 and 3125 —112 500,it is validated that the present parallel algorithm possesses quite high parallel efficiency and expansibility with good load balance and data communication efficiency.Three-dimensional complex hypersonic aerothermodynamics flows with different Mach numbers and Knudsen numbers past sphere-cone satellite body and complex wing-body assembled vehicle with big scale covering various flow regimes are computed and verified by the massive-scale parallel computation in high-performance computer systems.The computational results are found in high resolution of the flow fields and good agreement with the related DSMC,experimental and theoretical analysis,and the hypersonic complex flow mechanism and changing laws are revealed.It is indicated that the GKUA and massively parallel algorithm strategy possess good reliability in solving the Boltzmann model equation and simulating the complex multi-scale hypersonic flows covering the whole of flow regimes during spacecraft re-entering Earth’s atmosphere.%对 Boltzmann 方程碰撞积分物理分析与可计算建模，得到适于描述航天再入从外层空间到近地面各流域统一 Boltzmann 模型方程，提出求解 Boltzmann 模型方程统一算法高性能并行计算数学模型。发展离散速度空间区域分解大规模并行计算技术，分析统一算法变量依赖关系，建立可扩展并行计算方案；研究数据并行分布与并行执行特征，开展大规模并行化程序设计，并在小、中、大规模256～512、4096～20625CPU 及异构计算机500～45000、3125～112500进程并行算法测试，建立稳定运行于国产千万亿次超级计算机高性能可扩展大规模并行算法与航天器再入跨流域复杂气动力／热绕流问题并行化软件应用平台。通过对稀薄流到连续流再入飞行不同高度可回收返回式卫星飞行器、近空间大尺度机动飞行器跨流域绕流环境不同粒度高性能计算与验证，揭示大尺度复杂结构飞行器跨流区飞行稀薄过渡流区热流系数比连续、近连续流区热流系数随物面变化剧烈得多、大得多，发现该类飞行器后端面热流最大值发生在水平舵外侧拐角处，达驻点热流六分之一量级，提供了一个可靠求解航天器再入各流域高超声速绕流问题统一算法高性能并行计算应用研究方向。
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