喷嘴位置对脉冲爆轰发动机性能影响的试验研究

Experimental investigation on the location of nozzle on the performance of pulse detonation engine

为了研究喷嘴位置对脉冲爆轰发动机性能的影响,设计加工了直径为80mm的汽油/空气两相脉冲爆轰发动机(PDE),在PDE文氏管内不同位置安装喷嘴,进行了冷态雾化和热态燃烧转爆轰试验,分析了马尔文激光粒度仪测得的液滴尺寸分布和动态压力传感器测得的信号。试验结果表明:喷嘴的安装位置对脉冲爆轰发动机的性能具有显著影响;喷嘴安装在文氏管喉部时爆轰管内雾化混合效果最好,爆轰波峰值压力最大为3.5MPa,工作频率最高为30Hz;喷嘴安装在文氏管入口时爆轰管内雾化混合效果最差,爆轰波峰值压力最小为0.9MPa,工作频率最低为15Hz;在试验范围内,改善雾化混合效果有利于提高脉冲爆轰发动机的工作频率。研究结果对脉冲爆轰发动机的设计具有参考价值。

Pulse detonation engines （PDE）have received the widespread attention in recent years .However,there are many unresolved issues related to PDE.In order to achieve higher lev-els of thrust,PDEs require relatively small times to complete the liquid fuel atomization and mix-ture with air for increasing the operating frequency.But the nozzle location can have influence on the performances of atomization and mixing in PDE.To study the nozzle location on the perform-ances of PDEs,a gasoline/air two phases pulse detonation engine with a diameter of 80mm and a length of 1 .2 m was designed.PDEs consist of a mixing chamber,ignition and detonation cham-ber.And the venturi is installed in the mixing chamber.The experiments of atomization of the liquid fuel and deflagration to detonation transition（DDT）were carried out by installing a nozzle in three different locations of the venturi.The droplet size distribution in front of the ignition chamber measured by Malven laser mastersizer and signals measured by dynamic pressure sensor were analyzed.The experimental results show that the nozzle location has a significant influence on performances of the PDE.When the nozzle is installed in the throat of venturi,PDE has the best gasoline-air distribution（the sauter mean radius is less than 76.9μm）,the highest peak pres-sure of detonation wave（3.5MPa at 30Hz,5MPa at 10Hz）and the highest operating frequency （30Hz）.When the nozzle is installed in the expanding of venturi,the sauter mean radius is 85. 4μm,the peak pressure of detonation wave is 4.0MPa and the operating frequency is 20Hz. When the nozzle is installed in the entrance of venturi,PDE has the worst gasoline-air distribu-tion（the sauter mean radius is more than 93.4μm）,the lowest peak pressure of detonation wave （0.9MPa at 15Hz,1.1MPa at 10Hz）and the lowest operating frequency（15Hz）.In the experimental range,the operating frequency can be increased by improving the effect of atomization and mix-ing .The results offer reference for further research of deflagration to detonation transition mech-anism and atomization of the liquid fuel,design and operation of the pulse detonation engine.