爆轰波进入不可燃突扩管道行为研究

Detonation wave propagation in an incombustible abrupt expansion pipe

对爆轰波进入不可燃突扩管道后的传播规律及压力分布进行实验研究、数值模拟和理论分析.实验结果显示,爆轰波进入突扩管道一定距离后管道内压力会突升,随后压力曲线趋于平缓,在靠近封闭端面附近的压力又再次升高.采用自适应有限体积程序结合基元化学反应模型对流场进行了数值模拟.结果表明,爆轰波进入不可燃突扩管道后,化学反应停止,爆轰波衰减为激波.由于管道横截面的突然增大,激波在扩张段入口处发生绕射,平面波阵面逐渐演变为球面波阵面.该球面波阵面在向前传播的过程中与空腔上壁面先后发生规则反射和马赫反射.在发生马赫反射的位置,激波波后压力急剧升高.随马赫杆渐增,球面波阵面逐渐被抹平,最终再次形成平面激波.该平面激波到达封闭端面后又将发生反射,造成靠近封闭端面处的压力上升.

An investigation of propagation of hydrogen-oxygen mixture＇s detonation wave entering an abrupt expansion pipe was carried out experimentally and numerically. Experimental results show that the pressure will rise suddenly after detonation wave enters the abrupt expansion pipe, and the pressure will rise again at the pipe end. Selfadaptive finite volume method combined with kinetic chemical reaction model was programmed to simulate the flow field. Numerical results show that once the detonation wave enters the abrupt expansion pipe, chemical reaction stops, and detonation wave is attenuated into shock wave. The shock wave is diffracted around connection area, and its wave front is evolved into a spherical one. Regular reflection and Mach reflection occur subsequently due to the modified reflection angle. The pressure increases rapidly at the position of Mach reflection. Due to the Mach stem growth, the spherical wave flattens and evolves into a plane shock wave. When the plane shock arrives at the tube end, another reflection occurs and the pressure increases again.