脉冲来流下自激振荡喷嘴仿真研究

保证自激振荡喷嘴结构参数不变,利用FLUENT软件对脉冲来流喷嘴的振荡特性仿真分析。通过设定不同来流频率和来流速度,分析了腔内压力和速度变化趋势。仿真结果表明,脉冲来流会显著提高射流振荡效果,且当来流频率接近喷嘴装置固有频率时,出口压力峰值最大可提高3.2倍;来流速度与喷嘴结构存在一个最优匹配关系,使射流出口压力峰值达到最大。仿真结果与基于涡旋理论的自激振荡发生机理结论相符,对自激振荡喷嘴优化设计具有一定的指导意义。

Simulation and study on self-excited oscillation nozzle in upstream pulsed lfow

Remaining the structural parameters of the self-excited oscillation nozzle unchanged, the paper applied FLUENT to conduct simulation on the oscillation characteristics of the nozzle in upstream pulsed lfow, and analyzed the variation tendency of the pressure and the velocity in cavity at various lfow frequency and velocity. The simulation results showed: the pulsed lfow obviously enhanced the oscillation effects of the jet, and the pressure peak at nozzle outlet increased by 3.2 times at most while the lfow frequency was close to the natural frequency of the nozzle; there was optimal matching relationship between the lfow velocity and the nozzle structure, which made the pressure peak at nozzle outlet reached the maximum. The simulation results were in agreement with the conclusion of the self-excited oscillation mechanism based on the vortex theory. It possessed some guidance for the optimization design of the self-excited oscillation nozzle.