喷射或抽取气流抑制叶顶密封气流激振的实验研究  

Experimental investigation of the vibration suppression in a blade tip seal by air injection or pumping

作　　者：张强[1] 何立东[1] 张明[1] 

机构地区：[1]北京化工大学诊断与自愈工程研究中心,北京100029

出　　处：《北京化工大学学报（自然科学版）》2009年第1期85-88,共4页Journal of Beijing University of Chemical Technology(Natural Science Edition)

基　　金：国家自然科学基金(50675013);国家"863"计划(2007AA04Z422)

摘　　要：针对汽轮机叶片振动导致叶片断裂的问题,提出用喷射或抽取气流的方法来抑制叶顶密封气流激振。在叶片顶部密封装置上设计了带倾角的气流口,用于喷射和抽取气流。实验研究了在叶片顶部喷射或抽取气流对叶片振动的影响。当倾角小于30°时,在叶片顶部喷射气流加剧叶片振动;当倾角大于40°时,喷射气流明显地抑制了叶片振动,叶片振动量随着喷气压力的增加而减小,最低可减至初始振动量的81%。从叶片顶部抽取气流能够减小叶片振动10%以上;对于普通叶片,当抽气口采用正倾角时抽取气流抑制叶片振动的能力比采用负倾角时大;对于带冠叶片,抽取气流抑制叶片振动效果更好,减振能力可达23%,且叶冠宽度较大时减振效果更稳定。Air injection or pumping has been proposed as a way of reducing the vibrations in a blade tip seal in turbomachinery, and hence solve the problem of steam turbine blade fracture caused by blade vibration. In this work, a nozzle for air injection or pumping, with an adjustable nozzle angle, has been designed for the top seal. The influence of tip air injection or pumping on blade vibration has been investigated experimentally. The blade vibration is aggravated by the injection flow when the nozzle angle is less than 30°. In contrast, the blade vibration is gradually reduced with increasing injection pressure when the angle exceeds 40°, and the maximum reduction can be as high as 19 % of the initial vibration value. By pumping in the top seal, the blade vibration can be reduced by more than 10 %. For an ordinary blade, the reduction in vibration is better when pumping with a positive nozzle angle than with a negative angle. For a shrouded blade, the vibration reduction induced by pumping is enhanced, and up to 23 % of the initial vibration can be reduced. The vibration reduction induced by pumping is also enhanced for wider blade shrouds.

关 键 词：汽轮机 叶片 气流激振 喷气 抽气 抑制振动 

分 类 号：TK263.3[动力工程及工程热物理—动力机械及工程]