For the fixed length of low temperature plasma discharge zone with the same discharge zone gap

the volume size's influences on pulse detonation engine ignition initiating were studied. Propane was taken as fuel

air and pure oxygen as oxidant. The chemical reaction kinetics mechanism was fully considered in detail

and the low temperature plasma discharge zones were equivalent to high temperature and high pressure fire nucleus. Numerical simulations of the ignition initiating process were carried out by Fluent software. The lengths of the discharge zone of 20

40

60mm was comparatively analyzed. Results show that the low temperature plasma discharge zone equivalent to high temperature and high pressure fire nucleus is feasible

and complete ignition initiating process can be got; different lengths of discharge zone have strong influences on the initial flame form

the flame propagation speed and deflagration to detonation transition (DDT) time

but little influence on the detonation wave peak pressure.