槽底表面粗糙度影响干气密封性能的确定性方法  

Deterministic method for considering influence of bottom surface roughness on dry gas seal performance

作　　者：毛文元 宋鹏云[1,2] 邓强国[2] 许恒杰[2] MAO Wenyuan;SONG Pengyun;DENG Qiangguo;XU Hengjie(Faculty of Mechanical and Electrical Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650500,China;Faculty of Chemical Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650500,China)

机构地区：[1]昆明理工大学机电工程学院,云南昆明650500 [2]昆明理工大学化学工程学院,云南昆明650500

出　　处：《排灌机械工程学报》2018年第12期1294-1299,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(51465026)

摘　　要：为了研究槽底表面粗糙度对干气密封性能的影响,建立沿密封端面径向分布为正弦曲线的槽底表面粗糙度模型,考察在单个取样长度Lr内正弦波波长λ对密封性能的影响,确定了正弦波波数n=10,即波长λ=0. 08μm,采用近似解析法求解密封端面间隙的气膜压力分布,得到了不同槽深和不同膜厚下槽底表面粗糙度对干气密封端面开启力和泄漏率的影响规律.结果表明:针对所研究的工况,与光滑面相比,槽底面粗糙度Ra=0. 4μm时,开启力的最大相对误差(绝对值)为0. 12%,泄漏率的最大相对误差(绝对值)为0. 31%;槽底表面粗糙度Ra=0. 8μm时,开启力的最大相对误差(绝对值)为0. 50%,泄漏率的最大相对误差(绝对值)为1. 26%.这说明,一般工况下,槽底表面粗糙度Ra≤0. 8μm时,可忽略槽底表面粗糙度对干气密封性能的影响.而在非槽区气膜厚度h0<2μm的运行工况下,建议将槽底表面粗糙度Ra降低到0. 4μm以下.In order to study the influence of surface roughness at spiral groove bottom on the perfor-mance of dry gas seal,a groove bottom surface roughness model with a sinusoidal curve along the radial direction of the seal end surface was established,the influence of wavelengthλon the performance of dry gas seal was analyzed within the range of a sampling length Lr,and then the sine wave number n was determined,that is,n was 10 and the wavelengthλwas 0.08μm,the gas pressure distribution of the seal end surface gap was obtained by a approximate analytical method,the effect of surface roughness on the opening force and the leakage at different groove depths and gas film thicknesses were analyzed.As to the operating condition investigated,the results show that with respect to smooth groove bottom,the absolute value of maximum relative error for opening force is 0.12%and that for leakage rate is 0.31%when the groove bottom surface roughness Ra is 0.4μm;the absolute value of maximum relative error for opening force is 0.50%and that for leakage rate is 1.26%when Ra is 0.8μm.It indicates that the influence of bottom surface roughness on the sealing performance can be ignored when Ra≤0.8μm at common operation,whereas the surface roughness Ra of the groove bottom should be less than 0.4μm when the gas film thickness at non-groove region is smaller than 2μm.

关 键 词：螺旋槽 干气密封 表面粗糙度 开启力 泄漏率 

分 类 号：S227.9[农业科学—农业机械化工程] TB42[农业科学—农业工程]