二元超声速混压式进气道亚临界稳定裕度研究

Subcritical stability margin of two-dimensional supersonic mixed compression inlet

为了研究内收缩比和来流马赫数对二元超声速混压式进气道亚临界稳定裕度的影响规律及失稳机制,采用二维非定常仿真方法研究了内收缩比(ICR)为1.04~1.25的进气道在来流马赫数Ma0为2.4的条件下,以及内收缩比为1.08的进气道在来流马赫数为2.2~2.8条件下,其由稳态向失稳状态转变的过程。研究结果表明:(1)当Ma0=2.4时,在1.04≤ICR≤1.12内,随着ICR增加,亚临界稳定裕度ζ减小;1.16≤ICR≤1.25内,随着ICR增加,亚临界稳定裕度增大。(2)在内收缩比为1.08的条件下,马赫数变化引起的分离激波角和分离包再附压升两个关键因素变化共同主宰着进气道亚临界稳定裕度的变化趋势。(3)总体上,根据稳定亚临界初始状态的三相点无量纲高度?b是否大于1可将进气道的亚临界稳定裕度变化情形分为两类,当?b<1时,ζ随着?b的增加而减小;当?b> 1时,ζ随着?b的增加而增加。

To study the effects of internal contraction ratio(ICR)and incoming Mach number(Ma0)on the subcritical stability margin of a two-dimensional supersonic mixed compression inlet and its instability mechanism,a two-dimensional unsteady numerical simulation method was used to simulate the instability process of an inlet with an internal contraction ratio of 1.04 to 1.25 at an incoming Mach number of 2.4 and an inlet with an internal contraction ratio of 1.08 at an incoming Mach number of 2.2 to 2.8.The research results show that:(1)When Ma0=2.4,in the range of 1.04≤ICR≤1.12,with the increase of ICR,the subcritical stability marginζdecreases;in the range of 1.16≤ICR≤1.25,with the increase of ICR,the subcritical stability margin increases.(2)Under the condition that the internal contraction ratio is 1.08,the change of two key factors,the separation shock angle and the reattachment pressure rise of the separation bubble caused by the change of Mach number,jointly dominate the changing trend of the stable subcritical margin of the inlet.(3)In general,according to whether the dimensionless height of the triple point of the stable subcritical initial stateϵb is larger than 1,the changes of the stable subcritical margin of the inlet can be divided into two categories:Whenϵb<1,ζdecreases with the increase ofϵb;whenϵb>1,ζincreases asϵb increases.