亥姆霍兹上喷嘴出口结构对射流振荡特性的影响  

Effects of Helmholtz upper nozzle outlet structure on jet oscillation characteristics

作　　者：向美景 王晓川[1] 李登[1] 陈浩[1] 钱磊 XIANG Meijing;WANG Xiaochuan;LI Deng;CHEN Hao;QIAN Lei(School of Power and Mechanical Engineering,Wuhan University,Wuhan 430072,China)

机构地区：[1]武汉大学动力与机械学院,武汉430072

出　　处：《振动与冲击》2020年第7期74-80,155,共8页Journal of Vibration and Shock

基　　金：国家重点研发计划(2018YFC0808401)。

摘　　要：应用FLUENT软件对二维的亥姆霍兹喷嘴自振射流进行了模拟,并以此为基础研究了上喷嘴出口凸出部深入振荡腔对亥姆霍兹喷嘴自激振荡特性的影响。结果表明,上喷嘴的出口凸出部长度和喷嘴壁厚度都对自激振荡特性产生显著的影响。长度为0~0.15 D 1时,自振射流的脉动幅值可以提高20%~80%,提升幅度在射流速度较低时更大;凸出部长度为0.15~0.25 D 1时,射流振幅的提升逐渐降低;长度0.25~0.3 D 1时,射流振幅比普通喷嘴更低,稳定性下降;长度超过0.3 D 1时自振射流会完全消失。凸出部分喷嘴壁厚度在0<δ<0.1D 1范围内对射流性能几乎没有影响,但随着厚度δ的不断增大,性能会减弱,δ>0.15D 1时无法形成自振射流。总之,上喷嘴出口凸出可改善射流振荡性能,但长度和厚度需在一定范围内,否则无法产生自振射流。The software FLUENT was used to simulate a 2-D Helmholtz nozzle self-oscillating jet,and then effects of deep oscillatory cavity at the outlet protruding part of Helmholtz upper nozzle on its self-excited oscillation characteristics were studied.The results showed that upper nozzle outlet’s protruding part length and nozzle wall thickness have significant effects on self-excited oscillation characteristics;when protruding part length is 0-0.15 D 1,self-oscillating jet pulsation amplitude increases by 20%-80%;the lower the jet velocity,the more the amplitude increases;when protruding part length is 0.15-0.25 D 1,increase in jet amplitude drops gradually;when protruding part length is 0.25-0.3 D 1,jet amplitude is lower than that of ordinary nozzle,and jet stability drops;when protruding part length exceeds 0.3 D 1,self-oscillating jet fully disappears;when protruding part nozzle wall thickness is within the range of 0-0.1 D 1,wall thickness has little effects on jet performance,but with increase in wall thickness,jet performance weakens;when wall thickness is larger than 0.15 D 1,self-oscillating jet can’t be formed.

关 键 词：亥姆霍兹喷嘴 FLUENT 上喷嘴出口结构 长度和厚度 振荡特性 

分 类 号：TG137[一般工业技术—材料科学与工程]