Physico - Chemical Modelling in Nonequilibrium Hypersonic Flow Around Blunt Bodies
Physico - Chemical Modelling in Nonequilibrium Hypersonic Flow Around Blunt Bodies
复制标题
钝体周围非平衡高超声速流动的物理-化学建模
DOI：
--
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Y. Burtschell
中科院分区：
文献类型：
--
作者：
G. Tchuen;Y. Burtschell
新型空间运输飞行器的研制需要更好地了解钝头体的高超音速绕流情况，并对极高温下的热防护系统进行准确的预测。这个高超音速研究计划的复杂领域涉及到对再入流场的充分理解和控制。高速飞行的飞行器穿过低密度大气层的上层。在飞行器周围产生很强的弓形激波，将高动能转化为内能，从而提高气体的温度。因此，激波层是强烈的物理化学非平衡过程的场所，如振动激发、离解、电子激发，甚至电离和辐射现象。在这种典型的高超音速条件下，空气必须被认为是飞行器周围的等离子体，因为等离子体吸收无线电波，所以传统上会干扰飞行器和地面控制站之间的通信。这种流场的计算是一个具有挑战性的任务。如果不了解这些热化学不平衡现象以及它们如何影响飞行器的性能，那么这种高技术的成功概念是不可能的。其中一些信息可以从风洞和弹道靶场等实验设施或大规模战斗实验和/或数值模拟中获得。此外，由于无法精确模拟全尺寸高超音速飞行器周围的热化学非平衡流，小尺寸实验室试验受到严重限制，而且飞行试验费用太高，不允许广泛使用。因此，设计未来高超声速飞行器所需的气动热力学信息，大部分将来自于数值预测（最经济的方法），这是经过充分验证的一种合理的选择。高超声速钝头体热化学非平衡绕流的数值模拟，在驻点区的精确解是相当困难的。计算结果取决于热化学模型的选择和求解策略。一般来说，解决这些类型的流动的努力是基于Navier-Stokes方程和热化学现象之间的完全耦合。很多5
The development of new space transportation vehicle requires better knowledge of hypersonic flow around blunt bodies and an accurate prediction of thermal protection system for extremely high temperatures. The complex domain of this hypersonic research program concerns the fully understanding and the control of reentry flowfield. The vehicle flying with high velocity through the upper layers of the atmosphere with low density. A very strong bow shock wave around vehicle is generated and converted the high kinetic energy into internal energy, thus increasing the temperature of the gas. Therefore, shock layer is the site of intensive physico-chemical nonequilibrium processes such as vibrational excitation, dissociation, electronic excitation, even the ionization and radiation phenomena. Under this typical hypersonic condition, air must be considered as a plasma around the vehicle which perturbes traditionally the communication between the vehicle and ground control station because the plasma absorbs radio waves. The computation of such flowfield is a challenging task. The successful conception of such high technology would not have been possible without some knowledge of these thermochemical nonequilibrium phenomena and how they affect the performance of the vehicle. Some of these informations can either be obtained from experimental facilities such as wind tunnel and ballistic range, or large scale fight experiments, and/or numerical simulations. Moreover, small scale laboratory experiments are severely limited by impossible exact simulation of thermo-chemical nonequilibrium flow around a full scale hypersonic vehicle, and flight experiments are too costly to allow their widespread usage. Therefore, much of these aerothermodynamics informations needed to design future hypersonic vehicle will have to come from numerical predictions (the least expensive approach) which is a reasonable alternative after sufficient validations. The numerical simulation of hypersonic flow in thermochemical nonequilibrium past a blunt body presents considerable difficulties for accurate solutions in the stagnation region. The computational results depend on the choice of the thermochemical model and the strategy of resolution. Generally, efforts provided to solve these types of flows have been based on the full coupling between Navier-Stokes equations and the thermochemical phenomena. Many 5