Numerical investigation of DDT (deflagration to detonation transition) process in a valveless air-breathing pulse detonation engine

In order to investigate the flow characteristics of the DDT process in an air-breathing pulse detonation engine, two dimensional numerical simulation of the DDT process in a valveless air-breathing pulse detonation engine was carried out. The spark energy and the spark number were varied to investigate their effects on the DDT process. The mechanism that causes the difference in DDT process for different spark energies was analyzed. The simulation results indicated that: (1) The shock wave and reflected shock wave from the obstacles are the main reason that leads to the DDT; (2) the time of the DDT process decreases with increasing spark energy for the range of spark energy involved, but the length of the DDT remains almost the same; (3) when dual ignition sources were used, the length of the DDT was reduced compared with single ignition source of the same total spark energy.