环形爆震室中火焰加速数值模拟及验证

对带不同数量孔板的环形爆震室进行数值模拟,并通过试验对数值计算进行验证,来研究火焰加速现象、爆燃向爆震转变过程和不同当量比下起爆距离.数值计算采用二维轴对称非定常Navier-Stokes方程来模拟流体动力学过程.研究发现用较低的点火能量对火焰混合区的可燃气点火产生低速火焰,低速火焰向环形爆震室射流并改变方向向出口传播,火焰在孔板的阻碍作用以及火焰诱导激波和反射波的加速作用下,由层流变为湍流,湍流火焰与其诱导激波相互加强,最终引爆未燃混气;还对爆震波在孔板区的传播过程进行了分析,对不同当量比下的火焰速度和起爆距离进行了模拟研究. 

Numerical simulation and experimental study on flame acceleration in annular detonation duct

Numerical simulation of annular detonation duct with orifice plate of different numbers were carried out to study the phenomena of flame acceleration,the evolution of deflagration to detonation transition (DDT) and the detonation initiation distances at different equivalence ratios.Two-dimensional axisymmetric and unsteady Navier-Stokes equations were numerically simulated.The results of numerical simulation show that laminar flame is generated by low energy ignition in the region of flame mixing.The flame of low velocity jets to annular detonation duct,and propagates to the export with a changed direction.The laminar flame becomes turbulent flame in the obstruction of orifice plate and under the acceleration action of shock wave and reflected wave.The turbulent flame is strengthened mutually with its induced shock wave,and then detonates the unburned mixture.The progress of detonation propagation in the region with obstacles was also analyzed.The flame velocities and detonation initiation distances at different equivalence ratios were studied respectively.Through calculation and analysis,deep understanding of flame acceleration and DDT was obtained,and data for the mechanism of indirect initiation were accumulated.