关键词: 两相爆轰;脉冲爆震发动机;火焰射流;爆燃向爆震转变

Abstract: Ignition method based on turbulent hot jet is developed for two-phase pulse detonation engine (PDE). It is used to enhance a deflagration to detonation transition (DDT) time and distance. The turbulent hot jet is created by combustion in a pre-combustor which has a spark plug and a vaporizing tube. The vaporizing tube breathes and vaporizes two-phase mixture from main combustor to form combustible mixture, which is ignited by the spark to produce transverse hot turbulent jet into main combustor. In order to show the feasibility of this new ignition system, multi-cycle tests are carried on a pulse detonation engine model of 120mm in I.D. and 2500mm in length filled with gasoline-air mixture. By comparing with conventional spark system the new ignition method can shorten initiation time from 12.5 ms to 2 ms and DDT distance from 1350 mm to 775 mm. The effectiveness of the length and number of the pre-combustor on DDT has been conducted as well. A detailed study of the mechanism of detonation initiation by a turbulent jet of combustion products was demonstrated by shadowgraph observations in a 60 mm×60 mm square tube. Experimental results show that the turbulent hot jet can accelerate flame in combustible mixtures much faster than by spark directly.

Key words: Two phase detonation;PDE;Flame jet;DDT