| Based on the working principle of the new concept ram accelerator device,an ideal method of using the interaction between an oblique shock wave and a layered gas interface is proposed to achieve the normal starting of the device.A numerical scheme with high resolution and the algorithms for accelerating the chemical reactions during the interaction were used to simulate the interaction process on the frame of a MPI parallel architecture.The computational accuracy and computational efficiency of two parallel chemistry acceleration algorithms – TP and PLP – were investigated.The results show that both algorithms can meet the requirement of computational accuracy.The chemistry speedup ratios of these algorithm are ranged from 3 to 4,which suggests the obvious improvement of computational efficiency.The effects of inflow velocity(fight speed of projectile)and the filling amount of combustible premixed gas on the interaction process were examined.The time scale condition of the ignition during the process was proposed,and the thrust performances under different inflow velocities were estimated.The results show that the higher inflow velocity and more filling amount of flammable premixed gas are in favor of the occurrence of ignition.Both the chemical reaction and the gas interface instability contribute to the ignition process.When the chemical reaction delay time scale is smaller than the flow time scale,the ignition occurs.The flow field of combustion can be featured by a special mode in which the detonation wave and the non-premixed flame interface coexist.At higher inflow velocities,the thrust performance of the combustion field is higher and more stable. |
