A Study on Turbulent Heat Transfer Model in Aerodynamic Heating Fields with Dissociation

对于航天飞机和有翼飞行器的设计，气动热负荷的准确估计是最重要的问题之一。然而，由于缺乏合适的湍流热通量模型，这些估计是相当困难的。本研究的目的是进行必要的实验和计算，以建立可靠的湍流热流模型。本文主要开展了以下研究工作：1)建立了自由活塞高焓激波风洞。在压缩管末端实现了250-500巴的较高压力。此外，还完成了压缩管的特性和极强冲击波的产生。所产生的激波的最高马赫数可达34.5。(2)众所周知，自由活塞高焓激波风洞具有产生高温高压空气的能力，并且流动持续时间很短。WIND TU…的启动过程对非定常气动加热现象进行了数值模拟，揭示了高温化学反应对非定常气动加热现象的影响。(4)用化学非平衡条件模拟了激波与边界层的相互作用流场。壁面催化作用对壁面热流分布有很大影响。另外，随着非平衡度的增加，计算结果表明分离尺寸、热流分布和压力分布都可以挂起。(5)为了建立高超声速混合流场的湍流模型，对常规喷管的船尾流动结构和高温喷管流动进行了数值模拟。还考虑了考虑高温影响的湍流模型。(6)开展了降低高超声速气动热负荷的实验研究。较少

For the design of spaceplanes and winged vehicles the accurate estimation of aerodynamic heating load is one of the most important problems. However, those estimations are quite difficult du to the lack of proper turbulent heat flux modeling. The purpose of the present study is to conduct the necessary experiments and computations, which are requested in order to build reliable turbulent heat flux modeling. In the present studies the following studies have been conducted.1) Free-piston high enthalpy shock tunnel has been built. The higher pressure of 250 - 500 bars has been realized at the end of the compression tube. Also characteristics of compression tube and the generation of very strong shock wave have been completed. The top Mach number of the generated shock wave is up to 34.5.(2) It is well known that free-piston high enthalpy shock tunnel has capability to generate high temperature and high pressure air and also the flow duration is quite short. The starting process of wind tu … More nnel is numerically simtulated and the condition for the starting of the nozzle is estimated.(3) The unsteady aerodynamic heating phenomena have been simulated and the effects of high temperature chemical reaction on unsteady aerodynamic heating phenomena have been revealed.(4) The interacting flow fields of shock wave and boundary layer have been simulated with chemically non-equilibrium conditions. The wall catalytic generates quite large difference in heat flux distributions at the wall. Also as the degree of non-equilibrium is increased, the calculated results show that the size of separation, heat flux distribution and pressure distribution can be hanged.(5) For the purpose of the construction of turbulent modeling hypersonic mixing flow fields and boat tail flow structure and high temperature nozzle flow of conventional nozzle have been simulated. Also turbulent modeling with high temperature effects has been considered.(6) Experimental studies on the reduction of aerodynamic heating loads at hypersonic flows have been conducted. Less