厚液膜敞口型离心喷嘴动力学特性试验

为了解补燃循环液氧煤油发动机预燃室煤油离心喷嘴的动力学特性，开展了厚液膜敞口型离心喷嘴动力学响应特性试验研究。使用水为工作介质，通过改变喷嘴切向孔直径实现了旋流腔液膜厚度改变，通过脉动发生装置在喷嘴上游的供应管路上产生流量和压力振荡。使用脉动压力传感器记录了喷前压力的振荡特性，使用高速相机记录了旋流腔内流过程和喷注雾化的响应特性。研究发现：当扰动波较长时，旋流腔内液膜的厚度和喷嘴的喷雾角均周期性变化，厚液膜和薄液膜喷嘴内流过程对扰动波的动力学响应特性差别不大；随着扰动波长缩短，旋流腔内液膜局部"缩口"，"缩口"向下游传播并使喷雾过程出现Klystron效应；当扰动波较短时，相较于薄液膜喷嘴，厚液膜喷嘴旋流腔内流动过程对扰动波的耗散作用较弱，但厚液膜喷嘴的雾化过程对外加扰动始终不敏感。

Experimental on dynamic characteristics of an open-end swirl injector with thick liquid film

To understand the dynamic characteristics of the kerosene swirl injector in the pre-burner of the staged combustion LOX/kerosene rocket engine, dynamic characteristics in the open-end swirl injector with thick liquid film have been investigated experimentally. Using water as the working fluid, liquid films of different levels of thickness are obtained by changing the diameter of the tangential orifices of injectors. A flow pulsation generator is used to produce mass flow rate and pressure fluctuations in the feed line. The fluctuations of the pressure before injection are detected by a dynamic pressure sensor, and the dynamic response of the internal flow in the swirl chamber and the spray process are obtained by a high-speed camera. It is found that with long disturbance waves, the film thickness in the swirl chamber and the spray angle varies periodically, and at this moment there is little difference in the dynamic response between the thick and thin film injectors. With the decrease of disturbance wavelength, a portion of film with a "neck" is presented in the swirl chamber. The "neck" is propagated downstream, inducing the Klystron effect of spray after leaving the injector. When the disturbance wavelength was short, the disturbance waves are dissipated weaker in the swirl chamber with the thick film injector than with the thin film injector. However, the spray process of the thick film injector is not sensitive to any disturbance.