气相爆轰波冲击气固界面的透反射特性

Transmission and reflection characteristics of gaseous detonation waves impacting on gas-solid interface

为了研究气相爆轰波冲击气固界面过程中透射波和反射波的相关特性,建立爆轰波冲击气固界面的一维理论模型,对不同初始压力条件下爆轰波到达气固界面后的界面两侧的压力和界面速度变化进行分析。利用时空守恒元求解元方法对气相爆轰波冲击气固界面过程进行数值模拟,分析气体部分反射波的压力分布和速度变化规律及透射入固体中应力波的波形和波速特征,并搭建气相爆轰波冲击活塞实验装置进行进一步验证。结果表明:气体爆轰波到达气固界面后,在固体中透射指数形式的弹性波,并在界面处向气体区反射一道激波。爆轰波后的稀疏波与反射激波相交,削弱反射激波,最终形成稳定激波回传。气固界面在稀疏波和反射稀疏波的作用下,压力和速度逐渐下降,最终也形成稳定状态。在不同混气初始压力情况下,爆轰波冲击过程中产生的最高压力和爆压的比值基本保持不变。理论模型对特征点相关物理量的计算值和实验数据符合的较好。

The correlation characteristics of transmitted and reflected waves in the process of impact of the gas-solid interface by the gaseous detonation wave are of great engineering significance.A one-dimensional theoretical model was established to analyze the process of the detonation wave impacting the gas-solid interface.The changes in the pressure and interface velocity on both sides of the interface with different initial pressures after the detonation wave reaching the gas-solid interface were analyzed.The process of the gas-solid interface impacted by the gas-phase detonation wave was numerically simulated.The space-time conservation element and solution element(CE/SE)method and the elementary reaction mechanism were used to simulate the gaseous detonation,and the immersed boundary method(IBM)was used to simulate the fluid-structure interaction.The pressure distribution,rules of velocity change of partial reflection wave of gas,and the waveform and velocity characteristics of stress wave transmitted into solid were analyzed.An experimental device of the impact of the piston by gaseous detonation was built and used for further verification.The results show that after the gaseous detonation wave reaches the gas-solid interface,the elastic wave in the exponential form is transmitted in the solid,and a shock wave is reflected in the gas zone at the interface.The rarefaction wave after the detonation wave intersects with the reflected shock wave,which weakens the reflected shock wave.In this process,the pressure after the reflected shock wave decreases,and the wave velocity becomes faster.The pressure in the intersection area of the original and reflected rarefaction waves remains uniform.Finally,the reflected shock wave becomes stable,and the gas-solid interface forms a constant state.Under different initial pressures of the same mixture,the ratio of maximum pressure to detonation pressure in the process of the impact of the detonation wave remains stable.The theoretical model is consistent with the calculated values and experimental data of related physical quantities at the feature points.