新型自激扫掠喷嘴及其工作特性研究

Working Characteristics of a New Self-Excited Sweeping Nozzle

关键词:  自激扫掠喷嘴  流体振荡器  扰流柱  振荡频率  扫掠张角  高速阴影成像法  马尔文粒径测量

Key words:  Self-excited sweeping nozzle  Fluidic oscillator  Spoiler column  Oscillation frequency  Sweeping angle  High-speed shadowgraph method  Malvern particle size measurement

摘要:

针对涡轮、冲压发动机等空天动力装置对提高燃油雾化性能和油气掺混均匀度的迫切需求，提出一种内含扰流柱的新型自激扫掠喷嘴结构，能够实现0.5mm通径尺度下的自激发扫掠振荡液态燃料喷射。采用高速阴影成像、激光粒径测量等多种实验方法，研究了0.5mm特征尺度下，采用水和航空煤油介质时，新型自激扫掠喷嘴的质量流量、工作频率、扫掠张角、雾化粒径等参数随工作压降的响应变化情况。结果表明，此新型自激扫掠喷嘴在较宽的工作压力（0.05~5MPa）内均能够实现稳定的自激发扫掠振荡，产生50°以上的扫掠张角和1600Hz以上的振荡频率，且其扫掠张角和表征工作频率的斯特劳哈尔数St在较宽工作压力范围内保持恒定；与圆孔直射式喷嘴相比，其流量系数提高了12%，雾化能力实现了数量级的提升。本研究初步验证了新型自激扫掠喷嘴在空天动力装置典型应用环境和工况下的应用可行性。

Abstract:

In view of the urgent need for improving fuel atomization performance and oil-gas mixing uniformity of aero-aircraft engines and other aerospace power units， a new self-excited sweeping nozzle with spoiler column structure is proposed， which can realize self-excited sweeping oscillation liquid fuel injection at 0.5mm diameter scale. Using a variety of experimental methods such as high-speed shadowgraph imaging and laser particle size measurement， with water and aviation kerosene at the characteristic scale of 0.5mm， the response of mass flowrate， working frequency， sweeping angle and atomized particle size of the new self-excited sweeping nozzle to the working pressure drop was studied. The results show that the new self-excited sweeping nozzle can achieve stable self-excited sweeping oscillation in a wide working pressure range （0.05~5MPa）， resulting in a sweeping opening angle of more than 50° and an oscillation frequency of more than 1600Hz， and its sweeping angle and the Strouhal number characterizing the working frequency remain constant in a wide working pressure range. Compared with the plain-orifice nozzle， the flowrate coefficient increases by 12%， and the atomization capacity is improved by orders of magnitude. This study preliminarily verifies the application feasibility of the new self-excited sweeping nozzle under the typical application environment and working conditions of aerospace power units.