阻尼结构长扭叶片接触刚度与振动频率研究  

Contact stiffness and vibration frequency of long twisted blade with damping structure

作　　者：隋永枫 郑飞逸[1,3] 蓝吉兵 傅建中[1,2] 魏佳明 SUI Yong-feng;ZHENG Fei-yi;LAN Ji-bing;FU Jian-zhong;WEI Jia-ming(Polytechnic Institute,Zhejiang University,Hangzhou 310027,China;School of Mechanical Engineering,Zhejiang University,Hangzhou 310027,China;Hangzhou Steam Turbine Co.,Ltd.,Hangzhou 310022,China)

机构地区：[1]浙江大学工程师学院,浙江杭州310027 [2]浙江大学机械工程学院,浙江杭州310027 [3]杭州汽轮机股份有限公司,浙江杭州310022

出　　处：《机电工程》2022年第9期1278-1285,共8页Journal of Mechanical & Electrical Engineering

基　　金：国家自然科学基金资助项目(U1809219);浙江省重点研发攻关计划资助项目(2022C01118)。

摘　　要：长扭叶片是工业汽轮机的核心零部件,在进行长扭叶片设计时,由于阻尼结构长扭叶片的接触刚度和振动频率无法得到准确的预测,提出了一种带刚度修正系数的长扭叶片接触刚度计算方法。首先,基于赫兹接触与G-W模型,给出了长扭叶片接触刚度的计算公式,分析了主要参数对其接触刚度的影响,确定了刚度修正系数的求解方法;然后,进行了叶片频率试验,获得了叶片共振转速试验值;利用ANSYS软件对叶片进行了静态结构分析,获得了其接触面的法向压力;使用Matrix27单元模拟接触刚度,进行了叶片频率分析,并确定了刚度修正系数;最后,进行了叶片节径振动分析,获得了叶片1阶共振转速。研究结果表明:基于该方法获得的叶片1阶共振转速计算值与试验值的误差<5%;在考虑了围带厚度对计算精度的影响后,围带减薄7 mm,叶片1阶共振转速计算值与试验值的误差<1%;该结果证明,此方法能够准确预测阻尼结构长扭叶片的振动频率,其精度满足要求,具有良好的工程应用价值。Long twisted blade was the core component of industrial steam turbine.Aiming at the problem that the contact stiffness and the vibration frequency of long twisted blade with damping structures could not be accurately predicted,a contact stiffness calculation method with stiffness correction coefficient was proposed.Firstly,the contact stiffness calculation formula was given based on Hertz contact and G-W model,the influence of main parameters on contact stiffness was analyzed,and the solution method of stiffness correction coefficient was determined.Then,the blade frequency test was carried out,and the experimental values of blade resonance speed was obtained.The static structure analysis of the blade was executed by ANSYS software,and the normal pressure of the contact surface was obtained.The blade modal analysis was carried out by using Matrix27 element to simulate the contact stiffness,and the stiffness correction coefficient was determined.Finally,the modal analysis of blade pitch diameter was carried out,and the first-order resonant speed of blade was obtained.The research results indicate that the error between the calculated value and the experimental value of the first-order resonant speed of the blade based on this method is less than 5%;after considering the influence of the thickness of blade shroud on the calculation accuracy,the shroud is thinned by 7 mm,the error between the calculated value and the experimental value of the first-order resonant speed of the blade is less than 1%;it proves that the proposed method can accurately predict the vibration frequency of long twisted blades with damping structures,its accuracy meets the requirements,and it has good engineering application value.

关 键 词：汽轮机 围带厚度 叶片频率试验 接触刚度计算方法 刚度修正系数 静态结构分析 

分 类 号：TH123[机械工程—机械设计及理论] TK263.3[动力工程及工程热物理—动力机械及工程]