Comparative ignition characteristics of ethylene and gasolene in multi-cycle pulse detonation engine

To investigate the influence of the structure of multi-cycle pulse detonation engine(PDE) on its operation performance,experiments of ethylene-air and gasoline-air mixtures initiation process in the aero-valve PDE of 1050mm length and 40mm inner diameter were performed.The results show that the detonation wave can be successfully initiated in the ethylene-air with frequency of 25,30Hz and 40Hz,and C-J(Chapman-Jouguet) detonation wave can be achieved at the frequency of 40Hz with detonation wave propagation velocity of 1724m/s(less 5.6% than the C-J detonation wave velocity theoretical value 1832.45m/s) and peak wave pressure of 3.01MPa(higher 7.88% than the C-J detonation wave pressure theoretical value 2.79MPa).While the deflagration to detonation transition failed to complete in gasolene-air.By comparison of the two results,it was found that the evaporation process dominated the initiation process in liquid fuels,thus slowering the flame acceleration process in the detonation tube.More novel and optimized-designed reinforced-combustion devices for accelerating the flame should be developed,which may cause higher total pressure loss.Thus,atomization and evaporation to improve the quality of the mixture is a key technology for detonation in the liquid fuel.