自激吸气式脉冲射流装置压力及流动特性的研究

利用自制的射流试验平台对自激吸气式脉冲射流装置进行了冲击试验，测量了装置腔体上典型测点压力和靶心冲击力时间历程，运用高速摄像技术观测了装置内部水气流动过程，分析不同结构参数和运行参数下典型测点压力与冲击力脉冲效果，研究了典型测点压力、冲击力脉冲效果与水气流动过程之间的关系。研究结果表明：腔长、下喷嘴直径、工作压力和围压对吸气量有明显的影响；腔长和下喷嘴直径对碰撞体测点压力脉冲效果、冲击力时均值及其脉冲效果均有较大影响，存在着最佳结构参数使装置吸气量、冲击力时均值最大且脉冲效果最好；工作压力和围压对冲击力时均值及其脉冲效果影响较大；装置吸气后腔内形成了气水旋转涡团，气水旋转涡团与碰撞体测点压力和冲击力脉冲效果存在着明显的对应关系，解释了装置产生脉冲射流的原因。

Study of Pressure and Flow Characteristics for Self-excited Inspiration Pulse Jet Device

The impact test of self-excited inspiration pulse jet device was conducted by using homemade jet experiment platform. The time-varying process of typical measuring points pressure and target center impact were measured. The water-gas flow process inside the device has been recorded with a high-speed digital camera. The pulse effect of typical measuring point pressure and impact was analyzed under different structural parameters and operation parameters. The relationship among typical measuring points pressure, impact pulse effect and water-gas flow process was studied. The result shows that cavity length, nozzle diameter, working pressure and confining pressure had obvious influence on inspiration capacity. Cavity length and under nozzle diameter had significant influence on collision body measuring point pressure pulse effect, impact time-averaged value and pulse effect, and there were optimal structure parameters that make inspiration capacity, impact time-averaged value maximize and pressure pulse effect best. Work pressure and confining pressure had greater influence on the impact time-averaged value and pulse effect. The gas-water rotating vortex inside the cavity was formed after inspiration. There existed obvious corresponding relation between the gas-water rotating vortex and pulse effect of the collision body measuring point pressure and impact, so the reason of pulse jet was explained.