尾喷管对2-stage PDE性能影响的数值模拟

Investigation into the Effect of Nozzle on the 2-stage PDE Performance through Numerical Simulation

为研究尾喷管长度和扩张角度对两级脉冲爆震发动机凹面腔内激波会聚起爆及推力性能的影响,选取了一系列不同尾喷管长度和扩张角度的2-stage PDE模型进行数值模拟。单次爆震结果表明,尾喷管长度和扩张角度对2-stage PDE凹面腔中的射流碰撞和起爆过程影响很小。凹面腔的壁面压力和单位面积冲量随尾喷管长度增大而增加,且在较长形式的尾喷管中会出现多次激波相交和会聚,但是频率随尾喷管长度增大而减小。尾喷管壁面压力和冲量的轴向分量随扩张角度增大,凹面腔内的激波会聚和起爆频率不变。考虑凹面腔和尾喷管的综合作用,带有45°扩张角的尾喷管的2-stage PDE性能最好。

In order to study the influence of nozzle length and divergence angle on shock wave focusing detonation ignition and thrust of the 2-stage PDE resonator,a group models with a variety of nozzle lengths and divergence angles are studied by numerical simulation.Analytical results in a run indicate that the effect of nozzle length and divergence angle on jet collision and detonation initiation is very feeble.The average pressure and impulse on unit area of resonator is enhanced and times of shock wave focusing in the nozzle is increased as the nozzle length grows,though the frequency of shock wave focusing is decreased.The axial average pressure and impulse on unit area of nozzle wall is increased as the nozzle divergence angle grows,however,the frequency of shock wave focusing is almost unchanged.In consideration of the composite action of the resonator and the nozzle,the nozzle with a divergence angle of 45°presents the best 2-stage PDE performance.