热耗散变形下干气密封角向摆动稳定性的研究
|
摘要
干气密封系统角向摆动对密封端面造成磨损和影响密封的稳定性,通过数值求解和试验测试来探究密封角向摆动的稳定性规律。基于非线性振动理论,建立了气膜-密封环系统角向摆动模型,同时考虑热耗散变形对气膜厚度和刚度的影响。将气膜刚度和阻尼表示为含有摆角的多项式变量代入振动方程并设置无外激励,利用Floquet指数对非线性振动微分方程进行求解。在热耗散变形下的螺旋角为75°48'32″和无热耗散变形下的螺旋角为75°42'55″时,密封将会发生Hopf分岔,表明考虑热耗散变形下系统稳定运行时的螺旋角范围更大,热耗散变形对螺旋角和分岔点位置有一定影响。选取75°50'和75°两种螺旋角测试热耗散变形下角向摆动对密封端面和泄漏量的影响,发现考虑热耗散变形下螺旋角75°50'的干气密封端面擦痕严重,泄漏量不断增加,无法稳定,相比较螺旋角75°的泄漏量更大,说明热耗散变形对干气密封角向摆动有一定的影响,为干气密封的动态优化设计提供了理论指导。
The contact and wear between seal faces were caused by the angular wobble of a dry gas seal system and then will influence the stability,therefore,both the theoretical calculation and experiment were applied to study the stability. According to the theory of nonlinear vibration in consideration of the heat dissipation effect on the gas film thickness and stiffness,an angular wobble model of the gas film-sealing ring system was set up. In specific cases,the gas film stiffness and damping were expressed as multiple variables involving the wobby angle in order to obtain the differential equation of nonlinear vibration. Without external incentives,the system bifurcation was found through the Floquet index,and the influence of spiral angle of dry gas seal on the system stability was analysed. The hopf bifurcation will occur when the spiral angle reaches 75° 48' 32″ in consideration of thermal dissipation deformation and the spiral angle 75° 42' 55″without consideration of thermal dissipation deformation. The spiral angle stable ranges were acquired for the cases of under thermal dissipation or non-thermal dissipation. The spiral angle range to stabilize the system under heat dissipation and deformation is larger than that of no heat dissipation,which indicates that changes will happen for the bifurcation when considering the heat dissipation and deformation. Finally,the spiral angle 75°50'and 75° were chosen to process the specimen and an experiment was designed to observe the effect of angular wobble on the sealing faces and leakage. The dry gas seal with 75°50' spiral angle presents a bad serious abrasion face and continuall leakage. The experimental results were compared with those of the theoretical calculation to show that the spiral angle has certain interference on the sealing stability under thermal dissipation deformation,which provides a theoretic guidance for optimizing the dynamic design of dry gas seals.
The contact and wear between seal faces were caused by the angular wobble of a dry gas seal system and then will influence the stability,therefore,both the theoretical calculation and experiment were applied to study the stability. According to the theory of nonlinear vibration in consideration of the heat dissipation effect on the gas film thickness and stiffness,an angular wobble model of the gas film-sealing ring system was set up. In specific cases,the gas film stiffness and damping were expressed as multiple variables involving the wobby angle in order to obtain the differential equation of nonlinear vibration. Without external incentives,the system bifurcation was found through the Floquet index,and the influence of spiral angle of dry gas seal on the system stability was analysed. The hopf bifurcation will occur when the spiral angle reaches 75° 48' 32″ in consideration of thermal dissipation deformation and the spiral angle 75° 42' 55″without consideration of thermal dissipation deformation. The spiral angle stable ranges were acquired for the cases of under thermal dissipation or non-thermal dissipation. The spiral angle range to stabilize the system under heat dissipation and deformation is larger than that of no heat dissipation,which indicates that changes will happen for the bifurcation when considering the heat dissipation and deformation. Finally,the spiral angle 75°50'and 75° were chosen to process the specimen and an experiment was designed to observe the effect of angular wobble on the sealing faces and leakage. The dry gas seal with 75°50' spiral angle presents a bad serious abrasion face and continuall leakage. The experimental results were compared with those of the theoretical calculation to show that the spiral angle has certain interference on the sealing stability under thermal dissipation deformation,which provides a theoretic guidance for optimizing the dynamic design of dry gas seals.
引文
[1]GAD-El-HAK M.The fluid mechanics of micro devices-the freeman scholar lecture[J].Journal of Fluids Engineering,1999,121(1):5-33.
[2]BAI S X,MA C H,PENG X D,et al.Thermoelastohydrodynamic behavior of gas spiral groove face seals operating at high pressure and speed[J].Journal of Tribology,2015,137(2):02150201-02150211.
[3]HUANG W F,LIN Y B,GAO Z,et al.An acoustic emission study on the starting and stopping processes of a dry gas seal for pumps[J].Tribology Letters,2013,49(2):379-384.
[4]ZHANG H J,MILLER B A,LANDERS R G.Nonlinear modeling of mechanical gas face seal systems using proper orthogonal decomposition[J].Journal of Tribology,2006,128(10):817-827.
[5]THATTE A,ZHENG X Q.Hydrodynamics and sonic flow transition in dry gas seals[C].Proceedings of the ASME Turbo Expo:Turbine Technical Conference and Exposition,Düsseldorf,Germany,2014:1-13.
[6]LEE S C,ZHENG X L.Analyses of both steady behavior and dynamic tracking of non-contacting spiral-grooved gas face seals[J].Computers and Fluids,2013,88(12):326-333.
[7]KOLLINGER R.Theoretical and experimental investigation into the running characteristics of gas-lubricated mechanical seals[C].12th Intl.Conf.on Fluid Scaling,Brighton,UK,1989:307-22.
[8]MILLER B A,GREEN I.Semi-analytical dynamic analysis of spiral grooved mechanical gas face seals[J].Journal of Tribology,2003,125(2):403-413.
[9]ZHOU J F,FAN H L,SHAO C L.Experimental study on the hydrodynamic lubrication characteristics of magnetofluid film in a spiral groove mechanical seal[J].Tribology International,2016,95:192-198.
[10]丁雪兴,张海舟,张伟政,等.螺旋槽干气密封气膜振动测试与稳定性分析[J].振动、测试与诊断,2013,33(2):231-235.DING Xuexing,ZHANG Haizhou,ZHANG Weizheng,et al.Axial vibration test and analysis on gas film sealing ring system in dry gas seal[J].Journal of Vibration、Measurement and Diagnosis,2013,33(2):231-235.
[11]丁雪兴,陆俊杰,刘勇,等.热耗散变形下干气密封系统轴向振动稳定性分析[J].振动工程学报,2016,29(1):78-86.DING Xuexing,LU Junjie,LIU Yong,et al.Stability analysis on axial vibration of dry gas seal system under the thermo-elastic deformation considering the thermal dissipation[J].Journal of Vibration Engneering,2016,29(1):78-86.
[12]张伟政,俞殊荣,丁雪兴,等.干气密封系统角向摆动的稳定性及其振动响应[J].振动与冲击,2011,30(3):96-99.ZHANG Weizheng,YU Shurong,DING Xuexing,et al.Stability analysis and vibratory response of angular wobbly in the system of dry gas seal[J].Journal of Vibration and Shock,2011,30(3):96-99.
[13]刘蕴,殷国富,杜建媛,等.螺旋槽型干气密封系统轴向振动影响因素研究[J].四川大学学报(工程科学版),2016,48(增刊2):155-160.LIU Yun,YIN Guofu,DU Jianyuan,et al.Research of axial vibration of dry gas seal system with spiral groove[J].Journal of Sichuan University(Engineering Science Edition),2016,48(Sup 2):155-160.
[14]刘占生,夏鹏,张广辉,等.浮环密封运动机理及对轴系稳定性的影响[J].振动与冲击,2016,35(9):110-116.LIU Zhansheng,XIA Peng,ZHANG Guanghui,et al.Floating ring seals movement mechanism and its influence on stability of a rotor system[J].Journal of Vibration and Shock,2016,35(9):110-116.
[15]DING X X,LU J J.Theoretical analysis and experiment on gas film temperature in a spiral groove dry gas seal under high speed and pressure[J].International Journal of Heat and Mass Transfer,2016,96:438-450.
[16]BESKOK A,KARNIADAKIS G E,TRIMMER W.Rarefaction and compressibility effects in gas microflows[J].Journal of Fluids Engineering,1996,118(3):448-456.
[17]ZIRKELBACK N.Parametric study of spiral groove gas face seals[J].Tribology Transaction,2000,43(2):337-343.
[18]顾永泉.机械密封实用技术[M].北京:机械工业出版社,2002:141-145.
[19]丁雪兴,蒲军军,韩明君,等.基于二阶滑移边界的螺旋槽干气密封气膜刚度计算与分析[J].机械工程学报,2011,47(23):119-124.DING Xuexing,PU Junjun,HAN Mingjun,et al.Calculation and analysis of gas film stiffness in the spiral groove gas seal based on the second order slip boundary[J].Journal of Mechanical Engineering,2011,47(23):119-124.
[20]朱丽.螺旋槽干气密封系统非线性动力学行为研究[D].兰州:兰州理工大学,2011.
[2]BAI S X,MA C H,PENG X D,et al.Thermoelastohydrodynamic behavior of gas spiral groove face seals operating at high pressure and speed[J].Journal of Tribology,2015,137(2):02150201-02150211.
[3]HUANG W F,LIN Y B,GAO Z,et al.An acoustic emission study on the starting and stopping processes of a dry gas seal for pumps[J].Tribology Letters,2013,49(2):379-384.
[4]ZHANG H J,MILLER B A,LANDERS R G.Nonlinear modeling of mechanical gas face seal systems using proper orthogonal decomposition[J].Journal of Tribology,2006,128(10):817-827.
[5]THATTE A,ZHENG X Q.Hydrodynamics and sonic flow transition in dry gas seals[C].Proceedings of the ASME Turbo Expo:Turbine Technical Conference and Exposition,Düsseldorf,Germany,2014:1-13.
[6]LEE S C,ZHENG X L.Analyses of both steady behavior and dynamic tracking of non-contacting spiral-grooved gas face seals[J].Computers and Fluids,2013,88(12):326-333.
[7]KOLLINGER R.Theoretical and experimental investigation into the running characteristics of gas-lubricated mechanical seals[C].12th Intl.Conf.on Fluid Scaling,Brighton,UK,1989:307-22.
[8]MILLER B A,GREEN I.Semi-analytical dynamic analysis of spiral grooved mechanical gas face seals[J].Journal of Tribology,2003,125(2):403-413.
[9]ZHOU J F,FAN H L,SHAO C L.Experimental study on the hydrodynamic lubrication characteristics of magnetofluid film in a spiral groove mechanical seal[J].Tribology International,2016,95:192-198.
[10]丁雪兴,张海舟,张伟政,等.螺旋槽干气密封气膜振动测试与稳定性分析[J].振动、测试与诊断,2013,33(2):231-235.DING Xuexing,ZHANG Haizhou,ZHANG Weizheng,et al.Axial vibration test and analysis on gas film sealing ring system in dry gas seal[J].Journal of Vibration、Measurement and Diagnosis,2013,33(2):231-235.
[11]丁雪兴,陆俊杰,刘勇,等.热耗散变形下干气密封系统轴向振动稳定性分析[J].振动工程学报,2016,29(1):78-86.DING Xuexing,LU Junjie,LIU Yong,et al.Stability analysis on axial vibration of dry gas seal system under the thermo-elastic deformation considering the thermal dissipation[J].Journal of Vibration Engneering,2016,29(1):78-86.
[12]张伟政,俞殊荣,丁雪兴,等.干气密封系统角向摆动的稳定性及其振动响应[J].振动与冲击,2011,30(3):96-99.ZHANG Weizheng,YU Shurong,DING Xuexing,et al.Stability analysis and vibratory response of angular wobbly in the system of dry gas seal[J].Journal of Vibration and Shock,2011,30(3):96-99.
[13]刘蕴,殷国富,杜建媛,等.螺旋槽型干气密封系统轴向振动影响因素研究[J].四川大学学报(工程科学版),2016,48(增刊2):155-160.LIU Yun,YIN Guofu,DU Jianyuan,et al.Research of axial vibration of dry gas seal system with spiral groove[J].Journal of Sichuan University(Engineering Science Edition),2016,48(Sup 2):155-160.
[14]刘占生,夏鹏,张广辉,等.浮环密封运动机理及对轴系稳定性的影响[J].振动与冲击,2016,35(9):110-116.LIU Zhansheng,XIA Peng,ZHANG Guanghui,et al.Floating ring seals movement mechanism and its influence on stability of a rotor system[J].Journal of Vibration and Shock,2016,35(9):110-116.
[15]DING X X,LU J J.Theoretical analysis and experiment on gas film temperature in a spiral groove dry gas seal under high speed and pressure[J].International Journal of Heat and Mass Transfer,2016,96:438-450.
[16]BESKOK A,KARNIADAKIS G E,TRIMMER W.Rarefaction and compressibility effects in gas microflows[J].Journal of Fluids Engineering,1996,118(3):448-456.
[17]ZIRKELBACK N.Parametric study of spiral groove gas face seals[J].Tribology Transaction,2000,43(2):337-343.
[18]顾永泉.机械密封实用技术[M].北京:机械工业出版社,2002:141-145.
[19]丁雪兴,蒲军军,韩明君,等.基于二阶滑移边界的螺旋槽干气密封气膜刚度计算与分析[J].机械工程学报,2011,47(23):119-124.DING Xuexing,PU Junjun,HAN Mingjun,et al.Calculation and analysis of gas film stiffness in the spiral groove gas seal based on the second order slip boundary[J].Journal of Mechanical Engineering,2011,47(23):119-124.
[20]朱丽.螺旋槽干气密封系统非线性动力学行为研究[D].兰州:兰州理工大学,2011.