基于微元轨迹的密封动力特性系数理论识别方法  

A theoretical identification method for dynamic coefficients of seals based on infinitesimal trajectory of rotors

作　　者：顾乾磊 张万福[1] 张尧 陈璐琪 李春[1] 杨建刚[2] GU Qianlei;ZHANG Wanfu;ZHANG Yao;CHEN Luqi;LI Chun;YANG Jiangang(School of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;National Engineering Research Center of Turbogenerator Vibration,Southeast University,Nanjing 210096,China)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]东南大学火电机组振动国家工程研究中心,南京210096

出　　处：《振动与冲击》2019年第16期22-28,共7页Journal of Vibration and Shock

基　　金：国家自然科学基金(51875361;51575105;51676131)

摘　　要：提出一种基于微元轨迹的密封动力特性系数理论识别方法,结合瞬态涡动轨迹与动网格方法,得到转子在不同涡动频率下特定位置处所受气流力,采用微元理论求得密封动力特性系数。试验表明该研究理论所得密封直接刚度、阻尼系数、交叉刚度系数及有效阻尼系数均与试验结果吻合,尤其对衡量密封系统稳定性的有效阻尼系数,具有较高的识别精度。涡动频率对试验密封直接阻尼系数、有效阻尼系数和交叉刚度系数影响较小。计算结果表明密封最大间隙气流速度小于最小间隙,惯性力占主导作用,最大间隙具有较大压力,压力差加剧了转子偏心,造成密封系统存在静态不稳定性。An identification method using the infinitesimal trajectory method was proposed to predict rotor dynamic coefficients of annular gas seals.The transient solution combined with the moving grid method was unitized to obtain the fluid force at a specific position under different whirling frequencies.The infinitesimal method was then used to obtain the rotor dynamic coefficients,which agreed well with published experimental results.Particularly,the stability parameter of the effective damping coefficient could be solved precisely.Results show that the whirling frequency has little influence on direct damping coefficient,effective damping coefficient and cross-coupling stiffness coefficient.Results also show that the fluid velocity in maximum clearances is less than that in minimum clearances.The inertial effect dominants the flow field.Then it results in higher pressure that appears in maximum clearances.The pressure differential aggravates the eccentricity of rotors and results in the static instability of the seal system.

关 键 词：密封 动力特性系数 计算流体力学(CFD) 静态不稳定 气流激振 

分 类 号：TH212[机械工程—机械制造及自动化] TH213.3