用于幂律流体螺旋槽液膜机械密封性能的解析法
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摘要
为深入研究密封介质为非牛顿流体的螺旋槽上游泵送机械密封性能,以幂律流体为研究对象,基于Muijderman推导牛顿流体润滑轴承的端面压力分布表达式,把幂律流体二维定常流动雷诺方程和流量方程分别替换牛顿流体的表达形式,获得了密封端面流场的压力分布表达式,进而得到密封开启力、泄漏率等性能参数.将解析所得结果与采用Fluent模拟结果进行比较,两者数据吻合.再基于近似解析法,分别分析了稠度系数m和流性指数n对密封性能的影响,结果表明,密封开启力随流性指数n和稠度系数m的增大而增大.对于泄漏率而言,当密封胀塑性流体时,流性指数n和稠度系数m几乎没有影响.当密封假塑性流体时,处于较小膜厚时受稠度系数m和流性指数n的影响甚微,但处于较大膜厚时随流性指数n和稠度系数m增大而变大.
In order to deeply analyze the performance of the spiral groove upstream pumping liquid mechanical seal when the seal medium is non-Newtonian fluid,power-law fluid as the research object,the Reynolds equation and the two-dimensional steady flow flowing equation of Newtonian fluid were respectively replaced by the Reynolds equation and the flowing equation power-law based on Muijderman's pressure governing equation for Newtonian liquid lubricated bearing. Then the pressure distribution and the sealing performance parameters of the seal,such as the opening force and the leakage,were obtained. A comparison was made with the results for the approximate analytic method and the numerical simulation by Fluent software and the results between the two are consistent. The influence of consistency coefficient m and flow behavior index n on the seal performance was analyzed by the approximate analytic method. The results show that the opening force increases with the increasing of the flow behavior index n and the consistency coefficient m. When the sealed medium is pseudoplastic fluid,the effect of flow behavior index n and the consistency coefficient m on the leakage isweak at small film thickness,whereas the leakage increases with the increasing of the flow index n and the consistency coefficient m at large film thickness. The effects of flow behavior index n and the consistency coefficient m on the leakage can be ignored when the sealed medium is bulging plastic fluid.
In order to deeply analyze the performance of the spiral groove upstream pumping liquid mechanical seal when the seal medium is non-Newtonian fluid,power-law fluid as the research object,the Reynolds equation and the two-dimensional steady flow flowing equation of Newtonian fluid were respectively replaced by the Reynolds equation and the flowing equation power-law based on Muijderman's pressure governing equation for Newtonian liquid lubricated bearing. Then the pressure distribution and the sealing performance parameters of the seal,such as the opening force and the leakage,were obtained. A comparison was made with the results for the approximate analytic method and the numerical simulation by Fluent software and the results between the two are consistent. The influence of consistency coefficient m and flow behavior index n on the seal performance was analyzed by the approximate analytic method. The results show that the opening force increases with the increasing of the flow behavior index n and the consistency coefficient m. When the sealed medium is pseudoplastic fluid,the effect of flow behavior index n and the consistency coefficient m on the leakage isweak at small film thickness,whereas the leakage increases with the increasing of the flow index n and the consistency coefficient m at large film thickness. The effects of flow behavior index n and the consistency coefficient m on the leakage can be ignored when the sealed medium is bulging plastic fluid.
引文
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[7]邓成香.螺旋槽干气密封流固耦合分析[D].昆明:昆明理工大学,2013.
[8]宋鹏云.螺旋槽上游泵送机械密封性能影响因素分析[J].润滑与密封,2001,26(2):50-53.SONG Pengyun. An analysis of factors affecting the characteristics of a upstream pumping mechanical seal[J].Lubrication engineering,2001,26(2):50-53.(in Chinese)
[9]杨玄.非牛顿流体在旋流器中流动特性的数值模拟[D].青岛:中国石油大学,2010.
[2]宋鹏云,陈匡民,董宗玉,等.螺旋槽上游泵送机械密封性能的解析计算[J].润滑与密封,1999,24(4):5-7.SONG Pengyun,CHEN Kuangmin,DONG Zongyu,et al. A theoretical analysis of spiral groove upstream pumping mechanical seal[J]. Lubrication engineering,1999,24(4):5-7.(in Chinese)
[3]陈汇龙,王强,李雯瑜,等.基于Fluent的螺旋槽上游泵送机械密封三维微间隙流场数值模拟[J].润滑与密封,2012,37(2):16-18.CHEN Huilong,WANG Qiang,LI Wenyu,et al. Numerical simulation of 3-D flow in upstream pumping mechanical seals with spiral grooves based on fluent[J].Lubrication engineering,2012,37(2):16-18.(in Chinese)
[4] MUIJDERMAN E A. Spiral Groove Bearings[M]. New York:Springer-Verlag,1966:43-63.
[5]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(4):367-376.QIU Zugan,CHEN Boxian. Application of the unsteady reynolds equation for non-Newtonian fluids to dynamically loaded journal bearing[J]. Transactions of CSICE,1986,4(4):367-376.(in Chinese)
[6]陈学科,裘祖干.幂律流体的平均流动模型在粗糙径向滑动轴承中的应用[J].复旦学报(自然科学版),1995,34(6):671-677.CHEN Xueke,QIU Zugan. Application of the average flow model for power-law fluid to dynamically loaded rough journal bearing[J]. Journal of Fudan University(natural science),1995,34(6):671-677.(in Chinese)
[7]邓成香.螺旋槽干气密封流固耦合分析[D].昆明:昆明理工大学,2013.
[8]宋鹏云.螺旋槽上游泵送机械密封性能影响因素分析[J].润滑与密封,2001,26(2):50-53.SONG Pengyun. An analysis of factors affecting the characteristics of a upstream pumping mechanical seal[J].Lubrication engineering,2001,26(2):50-53.(in Chinese)
[9]杨玄.非牛顿流体在旋流器中流动特性的数值模拟[D].青岛:中国石油大学,2010.