Due to shearing action of the high-viscosity gas flow, the melting layer formed on the silica/phenolic insulation in the ramjet combustion chamber under high-temperature is ablated gradually away from the carbonized layers. A mathematical model for pneumatic removing process of the insulation in ramjet combustion chamber was established,and the erosion processs of insulation was numerically simulated. The results show that the insulation erosion is highly associated with velocity and temperature of local fuel gas flow; serious erosion occurs in backward position of the inlet, right in the middle of two neighbor inlets; though high temperature in the head of the combustor, the erosion there is not very serious due to relatively low gas velocity. Comparing the erosion rates at several position in the combustor, it is concluded that the gas temperature controls the formulation of liquid silicide layer, and the gas velocity controls the erosion rate.%硅基绝热层在补燃室高温环境中形成的熔融层受到高速气流的剪切作用,逐渐脱离炭化层,形成冲蚀现象.通过建立冲压发动机绝热层气动吹除过程的数学模型,对发动机绝热层的冲蚀过程进行了数值模拟.结果表明,冲蚀强度同当地气流温度及流速紧密相关；在进气道下游,两进气道之间绝热层受到的冲蚀作用最强；补燃室头部温度较高,但是由于气流流速较低,受气流冲蚀影响较小.对比表明,气流温度与速度共同决定的热流密度控制熔融层的形成速度,对于稳定发展的发动机流场,冲蚀作用主要受绝热层气流速度控制.
展开▼
