Abstract: An investigation of outlet-closed ramjet supersonic inlet oscillation was performed by method of CFD and wind tunnel experiments.The results showed that strong shock wave oscillation occurred in internal duct with close outlet.The oscillation frequency and amplitude was related to duct length and flight Mach number and this oscillation phenomenon was a kind of self oscillation.The Helmholtz resonator frequency equation was used to estimate the oscillation frequency.The equations extend linking with the CFD and experiment results.Then it can be used to predict the oscillation frequency and amplitude of the full-scale inlet-combustor in flight test.

Key words: Ramjet inlet;Shock wave oscillation;Computational fluid dynamics;Wind tunnel experiment;Helmholtz resonator

摘要： 采用计算流体力学和风洞试验两种手段,对冲压发动机出口封闭的多种超声速进气道内通道气流振荡现象进行了研究。结果表明,在一定的超声速范围内,封闭的进气道内通道发生了较强气流振荡现象,振荡频率、幅值和内通道长度、飞行马赫数有关,该振荡现象是一种自激振荡现象。利用亥姆霍兹共振器频率公式可以对封闭的进气道内通道振荡频率进行预估,并对其归纳出一种修正方法,可以结合模型试验结果对进气道和燃烧室内流振荡频率和幅值进行分析,为飞行试验提供预估和参考。

关键词: 超声速进气道;激波振荡;计算流体动力学;风洞试验;亥姆霍兹共振器