旋转叶片流固耦合振动对叶端定时测振的影响

Fluid-Structure Interactiong-based Vibration of Rotating Bladesand Its Influence on Blade Tip Timing

叶端定时是一种先进的旋转叶片在线振动监测方法,但其测量准确性受其测点位置变化影响较大,如何选取合适的测点具有重要研究价值。为考虑叶片颤振及其流固耦合振动对测点位置的影响,设置流场圆柱绕流产生涡阶,并对不同转速和裂纹位置下旋转叶片的扭转情况进行分析。计算比较离心载荷时正常叶片的扭转振动,流固耦合下正常叶片、裂纹叶片的扭转振动及叶端各点扭转偏移量对叶端定时测振测点位置的影响。结果表明:流固耦合作用下,转速和裂纹位置对叶片的扭转振动影响较大;叶端定时测振传感器在转速较低时应安装在靠近叶片前缘处,而转速较高时应安装在靠近叶端中间位置。

Blade tip timing(BTT)is an advanced online vibration monitoring method for rotating blades,but its measurement accuracy is greatly affected by the change of the sensing position.Therefore,how to select appropriate sensing points has important research value.In order to explore the impact of blade vibration on the sensing position under fluid-structure interaction,vortex steps were generated in the flow field around a cylinder and the torsional vibrations of rotating blades under different speeds and crack positions were studied.Torsional vibrations of normal blades and cracked blades were calculated and compared under different centrifugal loads and fluid-structure interaction.Furthermore,the effects of the torsional offset at the blade tip on the BTT sensing position were discussed.The simulation results show that the rotational speed and crack location have significant impacts on the torsional vibrations of the rotating blade under fluid-structure interaction.When the speed is low,the BTT vibration sensor should be installed near the leading edge of the blade.When the speed is high,it should be installed in the middle position near the blade tip.