多因素耦合作用下的高速气体绕流传热机理研究

The high speed gas flow around object is a typical multi-scale problem which involves both continuum and rarefied regions in the flow field.The flow and heat tansfer characteristics of high speed gas flow around object are affected by multi-factors including local rarefied effects,the shape of the object,structure and heat transfer characteristics of the material and chemical reactions. In present project,the numerical model and method for flow and heat transfer in high speed gas flow around object effected by mutli-factors will be established. And then study on key factors and mechanism of forming,development and variation of local rarefied region will be performed and the effects of local rarefied region on the flow and heat transfer characteristics of high speed gas flow around object will be investigated. Moreover, changes of flow and heat transfer parameters of high speed gas flow considering the coupled heat transfer of gas and solid will be disccused. Furthermore,the effects of chemical reactions will be considered when it is significant under certain conditions.Finally, flow and heat tansfer characteristics of high speed gas flow around object effected by multi-factors including local rarefied effects,the shape of the object,structure and heat transfer characteristics of the material and chemical reactions will be achieved and the accurate distributions of aerodynamic and heat transfer parameters along the surface of object will be predicted.

高速气体绕流问题是典型的跨越连续介质区和稀薄区域的多尺度、跨尺度问题。其流动传热现象受到多种因素的影响：局部稀薄效应、绕流体形状、绕流体材料的结构特性和传热特性及化学反应等。本项目的研究工作包括：构建多因素耦合作用下的高速气体绕流流动传热计算模型和计算方法；研究高速气体绕流中局部稀薄效应的产生、发展以及变化的规律，并分析关键的影响因素和作用机理，确定局部稀薄效应对绕流体表面气动参数和传热特性的影响程度；在考虑外流与绕流体本体耦合传热的条件下，研究高速气体绕流中的流动传热特征参数的变化规律；最后，在化学反应显著的情况下，考虑化学反应的影响。最终获得局部稀薄效应、绕流体几何特征、复杂结构材料传热特性和化学反应等多种因素耦合作用下，高速气体绕流中流动传热现象的变化规律和特点,准确预测绕流体表面的气动参数和传热特性参数分布。

研究了复杂计算区域网格的生成方法，采用解微分方程的方法生成适体坐标系下的网格。采用规正变量定义，将高阶SMART密度格式应用到可压缩算法中，研究了不同密度格式对可压缩算法的影响；对比了十三种高分辨率对流项格式，为不可压缩算法向全速域气体流动算法的拓展提供了参考依据，在此基础上，研究了可压缩SIMPLE算法和CLEAR算法在缩放喷管、圆弧凸拱通道内和外部物体绕流的流动问题，CLEAR算法成功地计算了入口马赫数为8的圆弧凸拱通道内的流动，在公开发表的文献中还是第一次见到。构建了DSMC-CFD耦合算法，并计算了高速外流绕流问题，分析了稀薄效应和流动-结构耦合传热过程。