一种组合动力装置爆震点火的三维数值模拟

Three-Dimensional Simulation of Detonation Ignition for a Combined Propulsion System

关键词:  组合动力  激波会聚  爆震起爆  三维数值模拟

Key words:  Combined propulsion system  Shock waves focusing  Detonation ignition  Three-dimensional simulation

摘要:

为在组合动力中寻求一种可靠、高频的爆震起爆方法，对超声速环形向心射流产生的激波在抛物形凹面腔内形成激波会聚，并起爆爆震的过程进行了三维的数值模拟。分析了环形向心射流的发展、前导激波的碰撞、激波会聚起爆爆震波及爆震波传播过程的流场变化情况。研究发现:除了激波的强度和混合气的性质这两个关键影响因素以外，在一定条件下，几何条件对能否起爆爆震有非常重要的影响。前导激波的碰撞和激波会聚产生的压力升高要远高于温度升高。激波在凹面腔内会聚形成的高能区域能直接起爆过驱动爆震波，起爆后过驱动爆震波迅速衰退成CJ爆震波。爆震波平均波速为1929.8m/s，波后压力为1.5MPa，温度为3400K。

Abstract:

Three-Dimensional numerical simulation of detonation initiation by supersonic annular jet induced shock waves focusing in parabolic concave was carried out to find a reliable and high frequency method of detonation ignition for a combined propulsion system. The development of annular supersonic jet，collision of leading shock waves，shock focus induced detonation initiation and propagation of detonation wave were analyzed. Besides the strength of shock wave and the property of reactive mixture，geometry plays an important role in the ignition of shock wave focus induced detonation in certain condition. The magnification of the pressure is greater than that of temperature during the shock waves intersection and focusing. High energy region induced by shock waves focusing is capable of igniting overdriven detonation directly，which rapidly decayed to CJ detonation. The velocity of detonation wave is 1929.8m/s. The pressure and temperature of the product is 1.5MPa and 3400K，respectively.