点火位置对两相旋转爆震波起爆特性影响的实验研究

Experimental Study on Effects of Ignition Positions on Initiation Characteristics of Two-Phase Rotating Detonation Waves

关键词:  旋转爆震  点火位置  起爆特性  传播模态  空筒形燃烧室

Key words:  Rotating detonation  Ignition position  Initiation characteristic  Propagation characteristic  Hollow combustor

摘要:

为了揭示两相旋转爆震波在空筒形燃烧室内的建立过程及传播特性，以航空煤油为燃料，富氧空气为氧化剂，在不同氧化剂供给条件下，实验研究了垂直预爆管安装位置（即点火位置）对旋转爆震起爆特性的影响。结果表明，在四个点火位置上（距喷注端面分别为20，40，60和90 mm，相对点火位置分别为0.15，0.30，0.46和0.69）均可触发并实现旋转爆震波的稳定传播，并观察到稳定爆震和不稳定爆震两种模态；旋转爆震波的建立过程均可以分为三个阶段：缓燃燃烧阶段、起爆阶段和稳定旋转爆震阶段。其中，缓燃燃烧阶段耗时最长，占爆震波建立时间的60%~80%，是制约RDE快速启动的关键环节；在相对点火位置为0.46处点火时，稳定爆震模态的建立时间最短且对应的工作范围最宽。

Abstract:

To investigate the initiation process and propagation characteristics of the two-phase rotating detonation waves in a hollow combustor， the effects of the ignition positions on the initiation characteristics have been experimentally studied by utilizing kerosene and oxygen-enriched air as fuel and oxidizer respectively under different oxidizer supply conditions when a pre-detonation tube is installed vertically. Experimental results indicate that the vertical pre-detonation tube can trigger and realize stable propagation of rotating detonation waves when four different ignition positions are employed （The axial distances from the injection plane are 20， 40， 60 and 90mm， and the relative ignition positions are 0.15， 0.30， 0.46 and 0.69， respectively）. In addition， two combustion modes were observed， i.e.， a stable detonation mode and an unstable detonation mode. The initiation process of the rotating detonation wave can be divided into three stages： deflagration stage， initiation stage， and stable rotating detonation stage. Among them， the deflagration stage takes the longest， accounting for 60% to 80% of the time to establish the stable detonation wave， which is the key to restricting the rapid initiation of the RDE. When the vertical pre-detonation tube is installed at the relative ignition position of 0.46， the shortest time of establishment of the stable detonation mode is obtained corresponding to the widest operating range.