离心喷嘴气涡固有声学频率预测

Prediction of natural acoustic frequency of gas core in centrifugal injector

为得到准确的离心喷嘴气涡固有声学频率,通过renormalization group(RNG)k-ε湍流模型和volume of fluid(VOF)气液两相流模型进行数值仿真研究。仿真结果表明将离心喷嘴与喷嘴出口锥形液膜视为一个声学系统可准确预测固有声学频率,修正后离心喷嘴固有声学频率计算公式可准确计算气涡中不同气体介质的1、2阶声学频率,误差在3%以内。室压扰动频率等于离心喷嘴固有声学频率时两者发生耦合共振,气涡压力脉动振幅增加量约为室压扰动幅值的16倍,气涡声学压力脉动可能传入上游供应系统,引起喷注不稳定。

In order to obtain accurate natural acoustic frequency of the gas core in centrifugal injector,numerical simulation was carried out by using renormalization group(RNG)turbulence model and volume of fluid(VOF)two-phase flow model.The simulation results showed that it could predict acoustic frequency of the centrifugal injector accurately by regarding the injector and conical liquid film at the exit of the injector as an acoustic system,and the modified formula of the acoustic frequency of the centrifugal injector can accurately calculate the first-order and second-order acoustic frequency of different gas media in the gas core,the error was within 3%.The coupling resonance occurred when the chamber pressure disturbance frequency was equal to acoustic frequency of the centrifugal injector,and the increase of the pressure amplitude in gas core was about 16 times of the chamber pressure disturbance amplitude,the gas core acoustic pressure pulsation may be introduced into the upstream supply system,resulting in the instability of the injection.