无阀两相脉冲爆震发动机循环过程实验分析

在无阀式以汽油为燃料,空气为氧化剂的脉冲爆震发动机(PDE)模型机上进行了低点火能量多循环实验研究,分析了无阀两相脉冲爆震发动机多循环工作过程。模型机热态试验提供了10~66 Hz爆震循环特征时间分配和爆震管内不同位置压力的变化过程。由于在两相系统中存在较长的点火延迟时间和DDT时间,发现无阀PDE存在较长的点火后填充时间。通过对两相爆震波的形成过程和排出过程的实验研究和分析,以及点火后填充时间,提出了新的无阀PDE特征时间分布。不同频率实验结果表明,从火花塞放电到下一个循环新鲜混合气开始填充这段时间基本不变,称之为极限周期。在该模型中,点火延迟时间和DDT时间占据了极限周期时间的大部分时间,进一步分析了提高循环频率的关键因素。

Experimental analysis on cycle processes of two-phase valveless pulse detonation engine

Experimental investigations were conducted on a two-phase valveless pulse detonation engine to explore the cycle processes.Gasoline and air were formed combustible mixture and was ignited by a spark with low energy release subsequently.Multi-cycle detonation test showed that characteristic times of the two-phase valveless PDE mock-up at operating frequency from 10 to 66Hz are different from others.Pressure evolution in the detonation tube was detected through pressure histories at different points along detonation tube at low operating frequency, and some characteristic times of cycle processes was obtained from pressure history at thrust wall from 10~66Hz.Due to long ignition delay time and DDT time for two-phase PDE,additional filling process after spark discharge was found.There exists limit cycle duration,which is equal to the difference of entire cycle duration and the pre-ignition filling time.Also,for increasing operating frequency,the most important factors were analyzed.