相贯线倒角结构对圆形封闭旁支管流致声共振影响的实验研究

Experimental Investigation of Chamfer Structure Effects onFlow-Induced Acoustic Resonance inCylindrical Closed Side Branch

相贯线倒角结构会对旁支管诱发的流致声共振现象的流场与声场特性造成影响。本文针对相贯线倒角大小对圆形封闭旁支管诱发的流致声共振特性的影响开展实验研究。所研究的3种相贯线倒角分别为无倒角、3 mm倒角和6 mm倒角。结果表明,随主管道流体Ma增大,旁支管内声共振频率呈阶梯状变化,各局部区域内声频率锁定,而相同阶声模态对应的控制频率与相贯线倒角大小无关;在实验Ma数范围内,随相贯线倒角增大,出现的声模态数减少,同阶声模态下最大共振声压幅值降低,声模态转变点对应的Ma增大;随相贯线倒角增大,发生声共振的St区间上下限和范围逐渐减小。

The chamfer structure will affect the flow field and the sound field characteristics of the flow-induced acoustic resonance phenomenon induced by the side branch pipe.The effects of chamfer structure on the acoustic resonance characteristics of closed side branches are investigated experimentally.Three different chamfers of 0,3 and 6 mm are investigated.The results indicate that the resonance frequency shows a lock-in phenomenon and the resonance frequency for a specified acoustic mode is insensitive to the edge geometry.In the investigated Ma range,the number of acoustic modes and the maximum amplitude of acoustic resonance for a specified acoustic mode decreases in the chamfer size.The critical Ma at the jump points of different acoustic modes increases in the chamfer size.For a certain hydraulic mode,the upper and lower boundaries of critical St both decrease in the chamfer size,and also the width of the St range.