Numerical study on wall pressure over cone region of blunt-nosed body in high enthalpy shock tunnel HIEST
Numerical study on wall pressure over cone region of blunt-nosed body in high enthalpy shock tunnel HIEST
复制标题
高焓激波风洞HIEST钝头体锥体区域壁压数值研究
DOI：
10.1016/j.ast.2015.12.015
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发表时间：
2016
影响因子：
5.6
通讯作者：
and Naofumi OHNISHI
中科院分区：
文献类型：
--
作者：
Tomoaki ISHIHARA;Yousuke OGINO;Takumi KINO;and Naofumi OHNISHI
探讨了高温高超声速流动中钝锥上计算表面压力过高的原因。在H0=15.6和10.1MJ/kg时，在自由活塞激波风洞中观察到了高估。灵敏度分析表明，在100~300K温度范围内降低上游平移温度，可以显著提高地面气压与实测值的一致性。由于上游平移温度较低，在喷管内的热化学非平衡计算中考虑了辐射冷却效应，使喷管出口平移温度降至约250K。以得到的流动变量作为上游边界条件，计算压力与实验数据吻合较好。为了弄清平动-振动弛豫时间、化学反应速率和上游化学成分等其他变量是否可能是造成差异的原因，采用了不确定性量化方法。结果表明，热化学模型和上游化学成分的这些参数对表面压力的一致性影响不大。结果表明，表面压力的差异是由于喷嘴区高温气体的辐射冷却效应造成的。
A cause of an overestimation of the computed surface pressure on a blunted cone in high-temperature hypersonic flow is explored. The overestimation was observed in a free-piston shock tunnel at the stagnation of H 0= 15.6 and 10.1 MJ/kg. The sensitivity analysis reveals that a reduction of the upstream translational temperature in the range of 100 to 300 K substantially improves the agreement of the surface pressure with the measured data. As the cause of the lower upstream translational temperature, radiative cooling effect is included in the thermochemical nonequilibrium calculation in the nozzle, the translational temperature at the nozzle exit is reduced to about 250 K. Using the obtained flow variables as the upstream boundary condition, the computed pressure agrees quite well with the experimental data. In order to clarify whether other variables such as translational–vibrational relaxation time, chemical reaction rates, and upstream chemical composition could be the cause of the discrepancy, uncertainty quantification is employed. It is shown that these parameters of the thermochemical model and upstream chemical composition have minor effect on the agreement of surface pressure. It is concluded that the observed discrepancy in the surface pressure is due to radiative cooling effect of high temperature gas in the nozzle region.