V型节流阀油流粘性加热及结构热变形分析
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摘要
作为液压系统的控制元件,节流阀的作用是通过改变节流口的过流面积来控制液压油流量,从而控制整个液压系统的全部功能。因此节流阀性能的可靠性,对整个液压系统是否能正常工作起到非常重要的作用。但在某些工作条件下,节流阀会发生热卡紧/热卡死失效故障,使阀套和阀芯之间的配合摩擦阻力增加,相对运动动作迟滞,节流阀控制精度严重降低,液压系统无法正常工作。本文以V型节流阀为研究对象,基于CFD和FEM相结合的流固耦合数值模拟方法对这一现象进行了深入研究。
本文首先通过数值模拟对节流阀热卡紧/热卡死现象的产生机理进行了合理的分析：即当粘性较大的液压油流入节流阀阀口时,由于槽口的节流作用液压油在节流槽内形成高速剪切流,因而粘性加热效应非常显著,节流槽口附近局部温度迅速升高,导致阀芯和阀套上槽口附近的区域在较短时间里受热膨胀变形,阀芯和阀套之间的配合间隙减小,从而出现热卡紧故障；当径向变形量进一步增大到大于阀芯和阀套的设计间隙时,则会发生阀芯热卡死现象。
然后,本文通过数值模拟系统地分析了液压油流动方向、节流槽结构参数和工作压差等因素对粘性加热导致节流阀热变形的影响规律,发现液压油流动方向和结构参数是影响节流阀阀芯热变形规律的主要因素；工作压力的增加使结构参数对节流阀热变形特性的影响放大。节流槽口温度峰值和径向变形极值在流入工况下随节流阀开度增大呈现先增大后减小的变化趋势,在流出工况下基本呈现持续增大的趋势；节流阀质量流量增大到饱和状态的过程中,流入工况最大径向变形极值高于流出工况。在相同的质量流量下,节流槽口径向变形量随着工作压差增大而加大。最后,本文动态分析了节流阀初始开启过程中阀套和阀芯的热变形过程。上述研究结果为节流阀的优化设计,以避免节流阀热卡紧/热卡死失效故障提供了理论基础,具有实际工程意义。
Throttle valve is used as control element to dominate hydraulic oil flux in fluid power transmission and control systems. The reliability of throttle valve is important to the system operation. However, throttle valve is source of high temperature in hydraulic system, and temperature increasing around notches due to viscous heating effect of hydraulically oil may cause valve heat stick or jam fault under some work conditions, which cause abnormal problems such as low efficiency, high energy and deadlock fault of sleeve and spool during operation. In this paper, this phenomenon was studied by numerical fluid-solid coupling method on throttle valve with V-notches
Firstly, this thesis explained generation mechanism by numerical simulation method: Heat deadlock fault of sleeve and spool happens to valve when radial deformation value exceeds the allowable radial clearance between the spool and valve sleeve, which because the viscous heating effect of the high speed and shear oil flow with large viscosity inside the valve is significantly, and then it causes serious thermal deformation of throttle valve around notches.
Afterwards, this paper analyzed the influence of flow directions, structural parameters as well as work pressure drop on temperature and thermal deformation distribution: The thermal deformation distribution inside V-notches is closely related to oil flow direction and notch structural parameters. And the change of pressure drop also produces affects as the secondary influencing element. Finally, the process of thermal deformation during valve opening period was investigated. Thus these studies provided theoretical reference for designers.
本文首先通过数值模拟对节流阀热卡紧/热卡死现象的产生机理进行了合理的分析：即当粘性较大的液压油流入节流阀阀口时,由于槽口的节流作用液压油在节流槽内形成高速剪切流,因而粘性加热效应非常显著,节流槽口附近局部温度迅速升高,导致阀芯和阀套上槽口附近的区域在较短时间里受热膨胀变形,阀芯和阀套之间的配合间隙减小,从而出现热卡紧故障；当径向变形量进一步增大到大于阀芯和阀套的设计间隙时,则会发生阀芯热卡死现象。
然后,本文通过数值模拟系统地分析了液压油流动方向、节流槽结构参数和工作压差等因素对粘性加热导致节流阀热变形的影响规律,发现液压油流动方向和结构参数是影响节流阀阀芯热变形规律的主要因素；工作压力的增加使结构参数对节流阀热变形特性的影响放大。节流槽口温度峰值和径向变形极值在流入工况下随节流阀开度增大呈现先增大后减小的变化趋势,在流出工况下基本呈现持续增大的趋势；节流阀质量流量增大到饱和状态的过程中,流入工况最大径向变形极值高于流出工况。在相同的质量流量下,节流槽口径向变形量随着工作压差增大而加大。最后,本文动态分析了节流阀初始开启过程中阀套和阀芯的热变形过程。上述研究结果为节流阀的优化设计,以避免节流阀热卡紧/热卡死失效故障提供了理论基础,具有实际工程意义。
Throttle valve is used as control element to dominate hydraulic oil flux in fluid power transmission and control systems. The reliability of throttle valve is important to the system operation. However, throttle valve is source of high temperature in hydraulic system, and temperature increasing around notches due to viscous heating effect of hydraulically oil may cause valve heat stick or jam fault under some work conditions, which cause abnormal problems such as low efficiency, high energy and deadlock fault of sleeve and spool during operation. In this paper, this phenomenon was studied by numerical fluid-solid coupling method on throttle valve with V-notches
Firstly, this thesis explained generation mechanism by numerical simulation method: Heat deadlock fault of sleeve and spool happens to valve when radial deformation value exceeds the allowable radial clearance between the spool and valve sleeve, which because the viscous heating effect of the high speed and shear oil flow with large viscosity inside the valve is significantly, and then it causes serious thermal deformation of throttle valve around notches.
Afterwards, this paper analyzed the influence of flow directions, structural parameters as well as work pressure drop on temperature and thermal deformation distribution: The thermal deformation distribution inside V-notches is closely related to oil flow direction and notch structural parameters. And the change of pressure drop also produces affects as the secondary influencing element. Finally, the process of thermal deformation during valve opening period was investigated. Thus these studies provided theoretical reference for designers.
引文
[1]陈愈,沈关耿等.液压阀.北京：中国铁道出版社,1982
[2]高殿荣,王益群.液压锥阀流场的有限元法解析.机床与液压,2000,(2)：12-14
[3]高殿荣,王益群,申功.液压控制锥阀内流场的数值模拟与试验可视化研究.机械工程学报,2002,(4)：66-70
[4]王林翔,陈鹰,路甬祥.液压阀道中的三维流体流动的数值分析.中国机械工程.1999,10(2)：127-129
[5]王林翔,.陈鹰,章明川.阀腔内速度场的PIV测量.机床与液压.2000(5)：32-33
[6].Tetsuhiro Tsukiji, Yoshihiko Yonezawa, Masahiko Soshino. Unsteady jet flow issuing from a spool valve for repeated valve opening and closing. FED-Vol.149, Separated Flows ASME 1993.189-197
[7]田奇.直喷式柱型液压阀流体稳态力的研究.中国机械工程,2002,13(13)：1102-1104
[8]罗亚敏,刘晓红,于兰英,石复元.液压比例阀阀芯V形槽口的CFD解析.流体传动与控制,2007,(5)：17-23
[9]Xiaoping Liu, Hirotsugu Kasuya, Yuusaku, etc. Flow analysis of hydraulic valve used in construction machinery. (In Japanese), Proceedings of JSME Ibaraki District Conference,2001
[10]Giuseppe Del Vescovo and Antonio Lippolis. Three-dimensional analysis of flow forces on directional control valves. International Journal of Fluid Power,2003, (2):15-24
[11]Giuseppe.Del Vescovo and Antonio Lippolis. A review analysis of unsteady forces in hydraulic valves.. International Journal of Fluid Power,2006, (3):29-39
[12]Massimo Borghi, Massimo Milani, Roberto Paoluzzi. Influence of notch shape and number of notches on the metering characteristics of hydraulic spool valves. International Journal of Fluid Power.2005(6):5-18
[13]Lugowsky, J. Experimental Investigation on the origin of flow forces in hydraulic piston valves.10th International conference on fluid power, BHR. Brugges, Belgium.1993
[14]冀宏, 傅新, 杨华勇.几种典型液压阀口过流面积分析及计算.机床与液压.2003,(5)：15-16
[15]冀宏,傅新,杨华勇,王庆丰.非全周开口滑阀压力分布测量研究.机械工程学报.2004,(4)：99-102
[16]冀宏,傅新,杨华勇,王庆丰.节流槽型阀口噪声特性试验研究.机械工程学报.2004,(11)：42-46
[17]冀宏.浙江大学博士学位论文.2005
[18]傅新,杜学文,邹俊,杨华勇,孔隙高速流动中的气穴观测与噪声特性.机械工程学报.2007,(4)：98-102
[19]高红,傅新,杨华勇.球阀阀口气穴流场的模拟与可视化研究.农业机械学报,2003,(3)：45-48
[20]刘晓红,柯坚,于兰英,王国志.液压滑阀径向间隙内温度分布的研究.机床与液压,2006,(11)：107-109
[21]李松.浙江大学硕士学位论文.2008
[22]付德熏,马延文.计算流体力学.北京：高等教育出版社,2002
[23]John D. Anderson, JR.计算流体力学入门.北京：清华大学出版社,2002
[24]王福军.计算流体动力学分析.北京：清华大学出版社,2004
[25]David C. Wilcox, Turbulence Modeling for CFD, Dew Industries,1998:21-25
[26]Chapman D R. Trends and pacing items in computational aerodynamics. AIAA 79-129
[27]Chen Y S. Viscous flow computations using a second order upwind differencing scheme. AIAA Paper:88-0417. AIAA 26th Aerospace Science Meeting. January.1988. A
[28]Launder, B. E. and Spalding, D. B., Mathematical models of turbulence, Academic Press, London, England,1972
[29]赵腾伦.ABAQUS6.6在机械工程中的应用.北京：中国水利水电出版社,2007
[30]石亦平,周玉蓉.ABAQUS有限元分析实例详解.北京：机械工业出版社,2006
[31]Patankar V S. Numerical heat transfer and fluid flow. Washington: Hemisphere, Publishing Corp; 1980
[32]梁永奇.机械制造中的传热与热变形基础.浙江：浙江大学
[33]杜学文.浙江大学博士学位论文.2008
[34]郭鸿志.传输过程数值模拟.北京：冶金工业出版社,1998
[35]林建忠.湍动力学.杭州：浙江大学出版社,2000
[36]彭楠,熊联友,陆文海,刘立强,汤建成,张亮. 低温节流阀的设计与计算.低温工程,2006,(5)：32-56
[37]陶文铨.数值传热学(第二版).西安：西安交通大学出版社,2001
[38]吴望一.流体力学(上册).北京：北京大学出版社,2005
[39]袁新明,毛根海,张土乔.阀门流道流场的数值模拟及阻力特性研究,水利发电学报,1999,67(4)：60-66
[40]章梓雄,董曾南.粘性流体力学.北京：清华大学出版社,1998
[41]周雪漪.计算水力学.北京：清华大学出版社,1995
[42]朱自强.应用计算流体力学.北京：北京航空航天学院出版社,1998
[43]Fluent Inc.. Fluent6.3 user's guide.2006
[44]Moin P, Kim J. The structure of the vorticity field in turbulent channel flow:Part 1, Analysis of instantaneous fields statistical correlations. J Fluid Mech,1985, 155:441—465
[45]Kim J, Moin P. The structure of the vorticity field in turbulent channel flow:Part 2, Study of ensemble-averaged fields. J Fluid Mech,1986,162:339-363
[2]高殿荣,王益群.液压锥阀流场的有限元法解析.机床与液压,2000,(2)：12-14
[3]高殿荣,王益群,申功.液压控制锥阀内流场的数值模拟与试验可视化研究.机械工程学报,2002,(4)：66-70
[4]王林翔,陈鹰,路甬祥.液压阀道中的三维流体流动的数值分析.中国机械工程.1999,10(2)：127-129
[5]王林翔,.陈鹰,章明川.阀腔内速度场的PIV测量.机床与液压.2000(5)：32-33
[6].Tetsuhiro Tsukiji, Yoshihiko Yonezawa, Masahiko Soshino. Unsteady jet flow issuing from a spool valve for repeated valve opening and closing. FED-Vol.149, Separated Flows ASME 1993.189-197
[7]田奇.直喷式柱型液压阀流体稳态力的研究.中国机械工程,2002,13(13)：1102-1104
[8]罗亚敏,刘晓红,于兰英,石复元.液压比例阀阀芯V形槽口的CFD解析.流体传动与控制,2007,(5)：17-23
[9]Xiaoping Liu, Hirotsugu Kasuya, Yuusaku, etc. Flow analysis of hydraulic valve used in construction machinery. (In Japanese), Proceedings of JSME Ibaraki District Conference,2001
[10]Giuseppe Del Vescovo and Antonio Lippolis. Three-dimensional analysis of flow forces on directional control valves. International Journal of Fluid Power,2003, (2):15-24
[11]Giuseppe.Del Vescovo and Antonio Lippolis. A review analysis of unsteady forces in hydraulic valves.. International Journal of Fluid Power,2006, (3):29-39
[12]Massimo Borghi, Massimo Milani, Roberto Paoluzzi. Influence of notch shape and number of notches on the metering characteristics of hydraulic spool valves. International Journal of Fluid Power.2005(6):5-18
[13]Lugowsky, J. Experimental Investigation on the origin of flow forces in hydraulic piston valves.10th International conference on fluid power, BHR. Brugges, Belgium.1993
[14]冀宏, 傅新, 杨华勇.几种典型液压阀口过流面积分析及计算.机床与液压.2003,(5)：15-16
[15]冀宏,傅新,杨华勇,王庆丰.非全周开口滑阀压力分布测量研究.机械工程学报.2004,(4)：99-102
[16]冀宏,傅新,杨华勇,王庆丰.节流槽型阀口噪声特性试验研究.机械工程学报.2004,(11)：42-46
[17]冀宏.浙江大学博士学位论文.2005
[18]傅新,杜学文,邹俊,杨华勇,孔隙高速流动中的气穴观测与噪声特性.机械工程学报.2007,(4)：98-102
[19]高红,傅新,杨华勇.球阀阀口气穴流场的模拟与可视化研究.农业机械学报,2003,(3)：45-48
[20]刘晓红,柯坚,于兰英,王国志.液压滑阀径向间隙内温度分布的研究.机床与液压,2006,(11)：107-109
[21]李松.浙江大学硕士学位论文.2008
[22]付德熏,马延文.计算流体力学.北京：高等教育出版社,2002
[23]John D. Anderson, JR.计算流体力学入门.北京：清华大学出版社,2002
[24]王福军.计算流体动力学分析.北京：清华大学出版社,2004
[25]David C. Wilcox, Turbulence Modeling for CFD, Dew Industries,1998:21-25
[26]Chapman D R. Trends and pacing items in computational aerodynamics. AIAA 79-129
[27]Chen Y S. Viscous flow computations using a second order upwind differencing scheme. AIAA Paper:88-0417. AIAA 26th Aerospace Science Meeting. January.1988. A
[28]Launder, B. E. and Spalding, D. B., Mathematical models of turbulence, Academic Press, London, England,1972
[29]赵腾伦.ABAQUS6.6在机械工程中的应用.北京：中国水利水电出版社,2007
[30]石亦平,周玉蓉.ABAQUS有限元分析实例详解.北京：机械工业出版社,2006
[31]Patankar V S. Numerical heat transfer and fluid flow. Washington: Hemisphere, Publishing Corp; 1980
[32]梁永奇.机械制造中的传热与热变形基础.浙江：浙江大学
[33]杜学文.浙江大学博士学位论文.2008
[34]郭鸿志.传输过程数值模拟.北京：冶金工业出版社,1998
[35]林建忠.湍动力学.杭州：浙江大学出版社,2000
[36]彭楠,熊联友,陆文海,刘立强,汤建成,张亮. 低温节流阀的设计与计算.低温工程,2006,(5)：32-56
[37]陶文铨.数值传热学(第二版).西安：西安交通大学出版社,2001
[38]吴望一.流体力学(上册).北京：北京大学出版社,2005
[39]袁新明,毛根海,张土乔.阀门流道流场的数值模拟及阻力特性研究,水利发电学报,1999,67(4)：60-66
[40]章梓雄,董曾南.粘性流体力学.北京：清华大学出版社,1998
[41]周雪漪.计算水力学.北京：清华大学出版社,1995
[42]朱自强.应用计算流体力学.北京：北京航空航天学院出版社,1998
[43]Fluent Inc.. Fluent6.3 user's guide.2006
[44]Moin P, Kim J. The structure of the vorticity field in turbulent channel flow:Part 1, Analysis of instantaneous fields statistical correlations. J Fluid Mech,1985, 155:441—465
[45]Kim J, Moin P. The structure of the vorticity field in turbulent channel flow:Part 2, Study of ensemble-averaged fields. J Fluid Mech,1986,162:339-363