基于JFO空化和幂律模型的螺旋槽液膜密封流体动压特性

doi:10.11949/j.issn.0438-1157.20170660

摘要/Abstract

摘要：

密封端面间润滑流体的非牛顿特性对密封的性能有重要影响。基于满足质量守恒的JFO空化边界条件及描述流体非牛顿特性的幂律模型，建立了考虑流体非牛顿特性的螺旋槽液膜密封数学模型。采用有限差分法对控制方程进行离散，通过SOR迭代方法对离散方程进行求解，得到了密封端面液膜压力分布。探讨了润滑流体的非牛顿特性对螺旋槽液膜密封的液膜承载能力、泄漏量、摩擦扭矩等性能参数及液膜中空化发生情况的影响规律。结果表明：随着幂律指数的增大，液膜承载能力先增大后减小，泄漏量和空化率增大，摩擦扭矩减小；幂律指数为0.96时，相对于牛顿流体，液膜承载能力提升约4.6%，密封端面空化率下降约98.6%，泄漏量下降约5.8%，摩擦扭矩增加约0.3%；随着操作参数的改变，不同幂律指数下的流体动压性能参数变化规律具有相似性；润滑流体的合理选择对液膜密封性能改善有重要意义。

关键词: 螺旋槽液膜密封, 幂律模型, 非牛顿流体, JFO边界条件, 流体动压特性

Abstract:

The performance of liquid film seals is significantly affected by non-Newtonian behavior of lubricating fluids at seal interface. A mathematical model of spiral groove non-Newtonian liquid film seal was established by combination of mass conservation at JFO cavitation boundary condition and power law model of non-Newtonian fluids. The governing equation was discretized by finite difference method and solved by SOR iterative algorithm to obtain liquid film pressure distribution. The effects of non-Newtonian fluids on sealing performance were analyzed, including load-carrying capacity, leakage, friction torque, and cavitation occurrence in liquid film. The results indicate that with the increase of power law index, the load-carrying capacity first increases then decreases but the leakage and cavitation rate always increase and the friction torque consistently decreases. At power law index n=0.96, non-Newtonian fluids had increase by 4.6% in the load-carrying capacity and 0.3% in the friction torque but decrease by 98.6% in the cavitation rate of sealing face and 5.8% in leakage than Newtonian fluids. When operating parameters were changed, non-Newtonian fluids with various power law indices showed similar trending behavior of liquid film hydrodynamic performance. Suitable lubricant selection is important to improve sealing performance of liquid films.

Key words: spiral groove liquid film seals, power law model, non-Newtonian fluids, JFO boundary condition, hydrodynamic performance

中图分类号:

TH117.2

王赟磊, 郝木明, 李振涛, 李勇凡, 孙鑫晖, 徐鲁帅. 基于JFO空化和幂律模型的螺旋槽液膜密封流体动压特性[J]. 化工学报, 2017, 68(12): 4665-4674.

WANG Yunlei, HAO Muming, LI Zhentao, LI Yongfan, SUN Xinhui, XU Lushuai. Hydrodynamic performance of spiral groove liquid film seals based on JFO boundary condition and power law model[J]. CIESC Journal, 2017, 68(12): 4665-4674.

参考文献 32

[1]	陈晓嵩. 螺旋槽液膜密封在炼油厂富气压缩机上的应用[J]. 润滑与密封, 2002, 27(5):91-94. CHEN X S. Application of spiral groove liquid seal on the rich gas compressor of refinery[J]. Lubrication Engineering, 2002, 27(5):91-94.
[2]	王衍, 孙见君, 马晨波, 等. 液膜及气膜非接触式机械密封的对比分析[J]. 润滑与密封, 2013, 38(3):111-116. WANG Y, SUN J J, MA C B, et al. Comparative analysis of non-contact mechanical seals with liquid and gas film[J]. Lubrication Engineering, 2013, 38(3):111-116.
[3]	刘铁汉, 蒋利军, 游艺, 等. 丁二烯螺杆压缩机泄漏分析与改造[J]. 化工机械, 2005, 32(2):113-116. LIU T H, JIANG L J, YOU Y, et al. Leakage analysis and modification of butadiene screw compressor[J]. Chemical Engineering & Machinery, 2005, 32(2):113-116.
[4]	QIU Y, KHONSARI M M. On the prediction of cavitation in dimples using a mass-conservative algorithm[J]. Journal of Tribology, 2009, 131(4):41702-41711.
[5]	赵中, 彭旭东, 盛颂恩, 等. 多孔扇形分布端面机械密封性能的数值分析[J]. 化工学报, 2009, 60(4):965-971. ZHAO Z, PENG X D, SHENG S E, et al. Numerical analysis of laser textured mechanical seals with a porous sector face[J]. CIESC Journal, 2009, 60(4):965-971.
[6]	李振涛, 郝木明, 杨文静, 等. 螺旋槽液膜密封端面空化发生机理[J]. 化工学报, 2016, 67(11):4750-4761. LI Z T, HAO M M, YANG W J, et al. Cavitation mechanism of spiral groove liquid film seals[J]. CIESC Journal, 2016, 67(11):4750-4761.
[7]	裘祖干, 陈伯贤. 非牛顿流体的非定常雷诺方程在动载径向滑动轴承中的应用[J]. 内燃机学报, 1986, (4):83-92. QIU Z G, CHEN B X. Application of unsteady Reynolds equation for non-Newtonian fluid in dynamic load journal bearing[J]. Transactions of CSICE, 1986, (4):83-92.
[8]	沈萌红, 周桂如. 假塑性流体润滑有限宽向心轴承的热流体动力分析[J]. 浙江大学学报(工学版), 1989, (3):377-387. SHEN M H, ZHOU G R. Thermal fluid dynamic analysis of a finite width mandrel lubricated by pseudoplastic fluid[J]. Journal of Zhejiang University (Engineering Science), 1989, (3):377-387.
[9]	EL-SHERBINY M, SALEM F, EL-HEFNAWY N. Optimum design of hydrostatic journal bearings(Ⅲ):Design procedure[J]. J. Eng. Appl. Sci.; (United States), 1986, 3:1/2.
[10]	SINGH C, NAILWAL T S, SINHA P. Elastohydrostatic lubrication of circular plate thrust bearing with power law lubricants[J]. Journal of Tribology, 1982, 104(2):243-247.
[11]	CHIPPA S P, SARANGI M. Elastohydrodynamically lubricated finite line contact with couple stress fluids[J]. Tribology International, 2013, 67(4):11-20.
[12]	SHARMA S C, RAJPUT A K. Effect of geometric imperfections of journal on the performance of micropolar lubricated 4-pocket hybrid journal bearing[J]. Tribology International, 2013, 60(7):156-168.
[13]	BOUYAHIA F, HAJJAM M, KHLIFI M E, et al. Three-dimensional non-Newtonian lubricants flows in sector-shaped, tilting-pads thrust bearings[J]. ARCHIVE Proceedings of the Institution of Mechanical Engineers Part J. Journal of Engineering Tribology 1994-1996(vols 208-210), 2006, 220(4):375-384.
[14]	SHARMA S C, YADAV S K. Performance analysis of a fully textured hybrid circular thrust pad bearing system operating with non-Newtonian lubricant[J]. Tribology International, 2014, 77:50-64.
[15]	王涛, 黄伟峰, 王玉明. 机械密封液膜汽化问题研究现状与进展[J]. 化工学报, 2012, 63(11):3375-3382. WANG T, HUANG W F, WANG Y M. Research and progress of mechanical seals operating with vaporization transition[J]. CIESC Journal, 2012, 63(11):3375-3382.
[16]	唐飞翔, 孟祥铠, 李纪云, 等. 基于质量守恒的LaserFace液体润滑机械密封数值分析[J]. 化工学报, 2013, 64(10):3694-3700. TANG F X, MENG X K, LI J Y, et al. Numerical analysis of LaserFace liquid lubricated mechanical seal based on mass conservation[J]. CIESC Journal, 2013, 64(10):3694-3700.
[17]	陈汇龙, 吴强波, 左木子, 等. 机械密封端面液膜空化的研究进展[J]. 排灌机械工程学报, 2015, 33(2):138-144. CHEN H L, WU Q B, ZUO M Z, et al. Overview on liquid film cavitation in mechanical seal faces[J]. Journal of Drainage and Irrigation Machinery, 2015, 33(2):138-144.
[18]	JAKOBSSON B, FLOBERG L. The finite journal bearing considering vaporization[J]. Wear, 1958, 2(2):85-88.
[19]	OLSSON K O. Cavitation in dynamically loaded bearing[J]. Wear, 1967, 55(2):1-60.
[20]	QIU Y, KHONSARI M M. Performance analysis of full-film textured surfaces with consideration of roughness effects[J]. Journal of Tribology, 2011, 133(2):021704(1-10).
[21]	赵一民, 魏超, 苑士华. 两种空化边界条件下的旋转密封润滑状态分析与试验[J]. 兵工学报, 2014, 35(12):1937-1943. ZHAO Y M, WEI C, YUAN S H. Analysis and experiment of lubrication condition of rotary seal based on two cavitation boundary conditions[J]. Acta Armamentarii, 2014, 35(12):1937-1943.
[22]	彭旭东, 佘宝瑛, 孟祥铠, 等. 不同排布方向性椭圆孔液体润滑机械密封性能的研究[J]. 摩擦学学报, 2013, 33(5):481-487. PENG X D, SHE B Y, MENG X K, et al. Sealing performance of liquid-lubricated mechanical seals with different arrangements inclined elliptical dimples[J]. Tribology, 2013, 33(5):481-487.
[23]	ELROD H G. A cavitation algorithm[J]. Journal of Tribology, 1981, 103(3):350-354.
[24]	BREWE D E. Theoretical modeling of the vapor cavitation in dynamically loaded journal bearings[J]. Journal of Tribology, 1986, 108(4):628-638.
[25]	VIJAYARAGHAVAN D, JR KEITH T G. Development and evaluation of a cavitation algorithm[J]. Tribology Transactions, 1989, 32(2):225-233.
[26]	FESANGHARY M, KHONSARI M M. A modification of the switch function in the elrod cavitation algorithm[J]. J. Chem. Soc., 2011, 32(6):5247-5251.
[27]	胡纪滨, 刘丁华, 魏超. 径向直线槽端面密封空化特性数值模拟[J]. 摩擦学学报, 2011, 31(6):551-556. HU J B, LIU D H, WEI C. Numerical simulation for cavitation of radial grooved face seals[J]. Tribology, 2011, 31(6):551-556.
[28]	赵一民, 苑士华, 胡纪滨, 等. 基于质量守恒边界条件的螺旋槽旋转密封性能分析[J]. 机械工程学报, 2014, 50(22):142-149. ZHAO Y M, YUAN S H, HU J B, et al. Performance analysis of spiral-groove rotary seals considering mass conserving boundary condition[J]. Journal of Mechanical Engineering, 2014, 50(22):142-149.
[29]	郝木明, 庄媛, 章大海, 等. 考虑空化效应的螺旋槽液膜密封特性数值研究[J]. 中国石油大学学报(自然科学版), 2015, 39(3):132-137. HAO M M, ZHUANG Y, ZHANG D H, et al. Numerical study on sealing performance of spiral groove liquid film seal considering effects of cavitation[J]. Journal of China University of Petroleum (Edition of Natural Science), 2015, 39(3):132-137.
[30]	DOWSON D. A generalized Reynolds equation for fluid-film lubrication[J]. International Journal of Mechanical Sciences, 1962, 4(2):159-170.
[31]	LEBECK A O. Principles and Design of Mechanical Face Seals[M]. John Wiley & Sons, 1991:109-249.
[32]	DIEN I K, ELROD H G. A generalized steady-state Reynolds equation for non-Newtonian fluids, with application to journal bearings[J]. Journal of Tribology, 1983, 105(3):385-390.