带挤压薄膜阻尼结构叶片的动态响应分析及试验研究

Theoretical and Experimental Investigation on Dynamic Response of Blade with Squeeze-Film Air Damper

关键词:  挤压薄膜阻尼  复刚度法  动态响应

Key words:  Squeeze-film air damper  Complex stiffness  Dynamic response

摘要:

为解决应用于航空发动机叶片的新型挤压薄膜阻尼结构的设计问题，针对带挤压薄膜阻尼结构叶片的动态响应及设计方法进行了理论分析和试验研究。引入复刚度法来表示叶片振动过程中气腔内气体域压强。根据挤压间隙流理论，推导了薄膜阻尼理论模型；分别对复刚度的实部和虚部积分获取势能和耗散能，从而推导出气腔内的气体域对气腔上、下表面固体域作用的阻尼系数和刚度系数。最后通过试验结果与仿真结果的对比，验证了带挤压薄膜阻尼结构叶片动态响应的分析方法，并初步获得了相关参数的设计规律，即薄膜厚度应小于0.2mm，薄膜中心应尽量靠近节线位置。

Abstract:

In order to design a squeeze-film air damper attached to a blade，a theoretical and experimental study has been conducted for the analysis on the vibrating response and the design method on blade with squeeze-film air damper. A complex stiffness was introduced to represent the air pressure in the cavity. Combined with the theory of squeeze-film，a theoretical model of the damper has been developed. The stain energy and dissipated energy were integrated from the real part and imaginary part of the complex stiffness to determine the stiffness coefficient and damping coefficient. An experimental study was carried out for a blade and the results were compared with the numerical prediction. The effects of thickness and location of film were obtained from the results. The thickness of film should be less than 0.2mm，and the centre of the film should be closed to the nodal line.