两相脉冲爆震发动机的燃油喷射、混合及其雾化研究

Injection,Mixing and Atomization Effects on Two-phase Pulse Detonation Engines

两相爆震燃烧近来得到了广泛的重视和关注,但在它走向应用之前仍有很多问题需要解决。燃油的喷射、混合和雾化对两相爆震燃烧的影响就是其中之一。本文利用激光喷雾测量仪分别就直射喷嘴与气动喷嘴研究了汽油的喷射雾化与混合雾化,得到了汽油的雾化粒度与供油量、供气量间的关系。利用CFD程序对混合室中油、气的混合特性进行了模拟,结果与试验结果非常吻合。结合脉冲爆震发动机模型机多循环爆震试验,发现汽油的粒度大小对脉冲爆震模型机的油气当量比、燃油填充比有显著的影响。

Detonation has received much attention lately because of its role in the primary combustion mechanism in rocket and air-breath pulse detonation engines （PDEs）. However, there are many unsolved issues related to the application of detonation combustion, for example, the fuel injection, atomization and mixing effects on two-phase detonation. This paper addresses the injection, mixing and atomization processes for plain-orifice injectors and twin-fluid air-assisted atomizers. A particle size meter based on laser light scattering is employed to measure mean droplet sizes. Relationship between droplet sizes and gasoline mass and gasoline/air ratio is arrived at. The twin-fluid air-assisted atomizer can produce much smaller mean droplet sizes than a plain-orifice injector. The mixing characteristics inside a mixing chamber obtained from three-dimensional simulation is consistent with the experiment, and with combination of the atomization data with the multi-cycle detonation data, droplet sizes of gasoline have a considerable effect on the gasoline-air equivalence ratio and gasoline filling ratio. The smaller droplet sizes, the lower the equivalence ratio is required to stable detonation. The smaller droplet sizes, the higher the gasoline filling ratio. As the detonation frequency increases, the effects of droplet sizes on equivalence ratio and filling ratio decrease, indicating a remarkable influence.