射流附壁振荡器能效分析与提升

摘要

By analysis,numerical simulation and experiment,it is proved that the energy loss of the j et wall-attached oscillator is mainly due to insufficient and inferior durative total pressure of the excitation stream.Satisfactory effect can not be achieved by various self-excitation ways relying on the feedback excitation of the shunt stream from principal j et.The effective method,which could greatly enhance the energy efficiency of the wall-attached oscillator,is put forward and validated.In this method,the high total pressure homologous gas with principal j et as excitation stream is modulated and imported from outside.Numerical simulation and experimental results show that the new external excitation oscillator has high energy efficiency index.Under the condition of expansion ratio of 2,the retention ratio of total pressure K could reach 85% and as high as 90% after the size parameters and excitation flow are optimized.They are much higher than those 75% by sonic wave type self-excitation oscillator,and 65% by feedback type oscillator.Besides,the oscillation frequency is easy to control.%通过分析、数值模拟和实验考察,揭示出射流附壁振荡器的能量损失大部分源于激励流的总压不足和持续性差.依靠主射流分流反馈激励的各种自激励方式皆无法达到较理想效果.提出并验证了从外调制引入与主射流同源的高总压气体作为激励流,是大幅提升附壁振荡器能效的有效方法.数值模拟和实验结果表明,新型外激励振荡器具有很高的能效指标,膨胀比为2的情况下,总压保持率K可达85%,尺寸参数和激励流量优化后可高达90%,远高于音波式自激励振荡器的75%和反馈式振荡器的65%的水平,且其振荡频率易控.