接触式机械密封界面泄漏机理分析

doi:10.11949/j.issn.0438-1157.20170908

摘要/Abstract

摘要：

旋转机械装备的密封性能对生产过程的能耗、效率和环保具有重要影响。基于逾渗理论，探讨了接触式机械密封界面空隙状态随动、静环表面分形参数和接触压力变化的规律。研究建立了密封界面单层网格微通道结构模型，指出了密封界面在接触压力作用下表现的逾渗、逾渗点和非逾渗3种状态。根据液体毛细管力和气体Knudsen数，提出了微通道内流体流动判据，分析了密封界面流体的流动阻力和泄漏流量，阐释了接触式机械密封界面泄漏机理。研究结果为接触机械密封优化设计和泄漏控制提供依据。

关键词: 机械密封, 界面, 空隙率, 微通道, 逾渗, 泄漏机理

Abstract:

The sealing performance of rotating mechanical equipment has an important impact on the energy consumption, efficiency and environmental protection during the production process. Based on the percolation theory, the variation law of the porosity distribution of the contacting mechanical seal interface with fractal parameters concerning the surface topography of rotary and stationary rings as well as the normal contact pressure was also discussed. A single-layer lattice leakage channel structure model of sealing interface was also established. A single-layer lattice leakage model referring to the channel structure of sealing interface was established, and three different states (percolating state, critical percolating state and non-percolating state) can be acquired under different contact pressure. According to the liquid capillary force and gas Knudsen number, the fluid flow criterion in the micro-channel was proposed, and flow resistance and leakage flow through sealing interface were analyzed, moreover, leakage mechanism of contacting mechanical seal interface was also illustrated. The research results provide a theoretical basis for the optimal design and leakage control of contacting mechanical seals in the next work.

Key words: mechanical seals, interface, voidage, microchannels, percolation, leakage mechanism

中图分类号:

TH136

孙见君, 陈国旗, 嵇正波, 马晨波. 接触式机械密封界面泄漏机理分析[J]. 化工学报, 2018, 69(4): 1528-1536.

SUN Jianjun, CHEN Guoqi, JI Zhengbo, MA Chenbo. Analysis on leakage mechanism for contacting mechanical seal interface[J]. CIESC Journal, 2018, 69(4): 1528-1536.

参考文献 31

[1]	WANG J L, JIA Q, YUAN X Y, WANG S P. Experimental study on friction and wear behaviour of amorphous carbon coatings for mechanical seals in cryogenic environment[J]. Applied Surface Science, 2012, 258(24):9531-9535.
[2]	GOILKAR S S, HIRANI H. Parametric study on balance ratio of mechanical face seal in steam environment[J]. Tribology International, 2010, 43(5/6):1180-1185.
[3]	SHIELS S. Failure of mechanical seals in centrifugal pumps[J]. World Pumps, 2002, 2002(429):20-22.
[4]	LEISHEAR R, JERALD N J, DAVID S D. Relationship between vibrations and mechanical seal life in centrifugal pumps[J]. Journal of Nervous & Mental Disease, 164(2):122-128.
[5]	KÄHKÖNEN A K, TENKANEN M. Experimental and numerical study of the lubrication regimes of a liquid mechanical seal[J]. Tribology International, 2015, 92(13):96-108.
[6]	KANDA K, SATO H, MIYAKOSHI T, et al. Friction control of mechanical seals in a ventricular assist device[J]. Biosurface and Biotribology, 2015, 1(2):135-143.
[7]	NETZEL J P, VOLDEN D. Non-contacting seals for critical service process pumps[J]. Sealing Technology, 1995, (15):7-11.
[8]	LEBECK A O. Contacting mechanical seal design using a simplified hydrostatic model[J]. Tribology International, 1988, 21(1):2-14.
[9]	BURGMAN D G. Original patented mechanical seal type still in service after 40 years[J]. World Pumps, 2003, (10):17-18.
[10]	包超英, 孟祥铠, 李纪云, 等. 基于渗流原理的液体润滑机械密封的泄漏率研究[J]. 流体机械, 2014, 42(11):24-28, 16. BAO C Y, MENG X K, LI J Y, et al. Study on leakage rate of liquid lubricated mechanical seal based on percolation theory[J]. Fluid Machinery, 2014, 42(11):24-28, 16.
[11]	包超英, 孟祥铠, 李纪云, 等. 基于多孔介质模型的机械密封静压泄漏特性分析[J]. 润滑与密封, 2015, 40(3):57-63. BAO C Y, MENG X K, LI J Y, et al. The leakage performance analysis of mechanical seals under hydrostatic pressures based on porous media model[J]. Lubrication Engineering, 2015, 40(3):57-63.
[12]	ELHANAFI S, FARHANG K. Leakage prediction in mechanical seals under hydrostatic opening condition[C]//Proceedings of ASME/STLE International Joint Tribology Conference, San Diego, California USA, 2007.
[13]	SUN J J, WEI L, FENG X, et al. Leakage prediction method for contacting mechanical seals with parallel faces[J]. Chinese Journal of Mechanical Engineering, 2010, 23(1):7-15.
[14]	MAYER E. Mechanical Seals[M]. London:Newnes-Butterworth, 1997.
[15]	LEBECK A O. Hydrodynamic lubrication in wavy contacting face seal:a two-dimensional model[J]. Journal of Lubrication Technology, 1981, 103(4):578-586.
[16]	孙见君, 顾伯勤, 魏龙. 基于分形理论的接触式机械密封泄漏模型[J]. 化工学报, 2006, 57(7):1626-1631. SUN J J, GU B Q, WEI L. Leakage model of contacting mechanical seal based on fractal geometry theory[J]. Journal of Chemical Industry and Engineering(China), 2006, 57(7):1626-1631.
[17]	BROADBEND S R, HAMMERSLEY J M. Percolation processes (Ⅰ):Crystals and mazes[C]//Mathematical Proceedings of the Cambridge Philosophical Society. Cambridge, England:Cambridge University Press, 1957, 53:629-641.
[18]	史建成. 基于逾渗理论的静密封建模方法与泄漏机理研究[D]. 北京:北京理工大学, 2015. SHI J C. Research on modeling and mechanism of static sealing based on percolation theory[D].Beijing:Beijing Institute of Technology, 2015.
[19]	CINAT P, PAGGI M, BORRI C. Percolation properties of the free volume generated by two rough surfaces in contact[C]//Ⅶ European Congress on Computational Methods in Applied Sciences and Engineering. 2016:1850-1855.
[20]	PERSSON B N, ALBOHR O, CRETON C, et al. Contact area between a viscoelastic solid and a hard, randomly rough, substrate[J]. Journal of Chemical Physics, 2004, 120(18):8779-8793.
[21]	AHARONY A, STAUFFER D. Introduction to Percolation Theory[M]. Taylor & Francis, 2003.
[22]	陆建花. 接触式机械密封界面间泄漏流体流动特性研究[D]. 南京:南京林业大学, 2016. LU J H. Study on leakage flow characteristics between contact mechanical sealing interfaces[D]. Nanjing:Nanjing Forestry University, 2016.
[23]	PERSSON B N. Fluid dynamics at the interface between contacting elastic solids with randomly rough surfaces[J]. Journal of Physics:Condensed Matter, 2010, 22(26):2181-2188.
[24]	PERSSON B N J, YANG C. Theory of the leak-rate of seals[J]. Journal of Physics:Condensed Matter, 2008, 20(31):1959-1964.
[25]	BOTTIGLIONE F, CARBONE G, MANTRIOTA G. Fluid leakage in seals:an approach based on percolation theory[J]. Tribology International, 2009, 42(5):731-737.
[26]	BOTTIGLIONE F, CARBONE G, MANGIALARDI L, et al. Leakage mechanism in flat seals[J]. Journal of Applied Physics, 2009, 106(10):799-808.
[27]	袁腾, 陈卓, 刘文济, 等. 毛细力学在超亲水膜分离过程中的应用及力学模型[J]. 华南理工大学学报(自然科学版), 2014, 42(10):82-89. YUAN T, CHEN Z, LIU W J, et al. Application of capillary mechanics to separation process of superhydrophilic membrane and its mechanical model[J]. Journal of South China University of Technology (Natural Science Edition), 2014, 42(10):82-89.
[28]	蔡仁良, 顾伯勤, 宋鹏云. 过程装备密封技术[M]. 北京:化学工业出版社, 2006. CAI R L, GU B Q, SONG P Y. Process Equipment Sealing Technology[M]. Beijing:Chemical Industry Press, 2006.
[29]	FINNEMORE J E, FRANZINI J B, ALLAIRE P. 流体力学及其工程应用[M]. 北京:机械工业出版社, 2006. FINNEMORE J E, FRANZINI J B, ALLAIRE P. Fluid Mechanics with Engineering Applications[M]. Beijing:China Machine Press, 2006.
[30]	张程宾, 陈永平, 施明恒, 等. 表面粗糙度的分形特征及其对微通道内层流流动的影响[J]. 物理学报, 2009, 58(10):7050-7056. ZHANG C B, CHEN Y P, SHI M H, et al. Fractal characteristics of surface roughness and its effect on laminar flow in microchannels[J]. Acta Physica Sinica, 2009, 58(10):7050-7056.
[31]	夏清, 陈常贵. 化工原理(上册)[M].天津:天津大学出版社, 2009. XIA Q, CHEN C G. Principles of Chemical Engineering (Volume One)[M]. Tianjin:Tianjin University Press, 2009.