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高温真实气体效应所引起气体比热比γ的降低被认为是导致航天飞机“上仰异常”的主要原因.为详细研究此问题,本文数值求解了Euler方程,化学反应源项采用有限速率模型,考虑了5个组分、17个基元反应.研究结果表明采用低比热比气体CF4作为实验气体会导致膨胀区的压力分布与真实气体效应的影响规律不一致,并不能反映出“上仰异常”现象的本质.在高温真实气体效应的影响下,化学反应所带来的影响大于振动激发的影响,对于y方向半模压力积分Cay来说是3.8倍,而对于半模力矩积分系数Cam来说是1.7倍.对比分析表明,热化学反应导致的比热比分布不均衡是导致“上仰异常”现象出现的根本原因.
To reduce the gas specific heat ratio γ caused by the high-temperature real gas effect, it is considered that the Euler equation is solved numerically in this paper. The chemical reaction source term uses a finite rate Model, considering five components and 17 elementary reactions.The results show that the effect of the pressure distribution in the expansion zone on the real gas effect is inconsistent with the low specific heat ratio CF4 gas, which does not reflect the “ Uplift anomalies. ”Under the influence of the high-temperature real gas effect, the influence of the chemical reaction is larger than that of the vibrational excitation, which is 3.8 times for the y-direction half-pressure Cay and 3.8 times for the half-mode moment Integral coefficient Cam is 1.7 times.Comparison analysis shows that the thermoelectric reaction caused by the uneven distribution of specific heat ratio is caused “Yang Yang abnormal ” phenomenon appears the fundamental reason.