磁脂密封磁场与传热数值研究
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摘要
采用低沸点液体介质冷却解决低转速、高扭矩电机冷却技术,是减少电机体积,提高电机效率较为有效的措施,尤其对我国大型电机石化行业,船用机械等可将庞大的减速箱去掉,极大地优化结构设计,降低设备成本。
电机中冷却液的密封成为该技术的一个关键点。传统密封装置很难达到要求,针对这种工作环境我们提出采用新型密封技术,即磁脂密封。不同间隙和不同齿形的密封结构会影响磁场分布和密封耐压能力；而转轴和磁极的温度场对密封寿命有至关重要的影响。
本文首先采用ANSYS分析软件,对磁脂密封不同结构的模型进行磁场的数值模拟,通过得出的实际密封简化耐压公式计算该密封的耐压能力,结果表明：磁脂密封能力好于普通磁流体密封,且由于磁脂密封的磁极与转轴间隙可以更大,所以适用于转轴径向跳动量大的场合,应用范围更广泛。研究表明,磁脂密封失效发生在什么位置是与密封间隙有关系的。双斜齿的密封耐压能力稍强,单斜齿次之,矩形齿稍弱；但三种不同齿形的耐压能力相差不大。由于矩形齿加工工艺简单,性能容易保证,因此在实际应用中一般选用矩形齿；极齿宽度太大或太小都会降低密封能力。对于本实验装置,极齿宽度取2-4mm较为合理；在一定范围内,不同的极齿高度对对密封压差影响不大。
建立了实验装置的二维传热模型,并对该模型进行数值求解,获得转轴、磁极和永磁铁内部的温度分布,结果表明：受冷却水的影响,冷却水槽附近磁极温度明显低于转轴的温度；温度最低处发生在与氟利昂接触的内侧磁极,最低温度为80℃；由于转轴与磁铁之间为空气,导热系数低,因此永磁铁的温度较低。
The liquid cooling technology of low boiling point that solved the low speed and high-torque motor cooling is an effective traditional craft of reducing the motor size and improving motor efficiency. The use of this technology can remove the large gear box, greatly optimize the structure design and reduce equipment costs for China's large-scale electrical and petrochemical industries, marine machinery.
Sealing motor cooling fluid is a key point of the technology. The generally traditional seal is difficult to meet the requirements. In view of this working environment, we propose using new sealing technology-the high viscous and non-Newtonian magnetic fluid sealing. Different sealing gap and different tooth structure will affect the magnetic field distribution and sealed pressure capabilities; while the temperature field of shaft and pole have a critical influence on sealing life.
In this paper, high viscous and non-Newtonian magnetic fluid sealing different gap and different tooth structure was analyzed by using the finite element software package ANSYS. The sealing pressure was calculated by the equation of actual pressure resistance, the results show that the seal capacity of the high viscous and non-Newtonian magnetic fluid sealing is better than the ordinary magnetic fluid sealing and the high viscous and non-Newtonian magnetic fluid sealing is applicable to the occasions of large axial-radial pulse volume and has wide range of applications because of the large gap between of the magnetic pole and the shaft. The location of failure has relationship with the seal gap. The seal pressure capability of double-oblique tooth is slightly stronger than single-oblique tooth, and the seal pressure capability of rectangular tooth is weakest, but the seal pressure capability of three different teeth is or less. As machining process simply and easy to guarantee performance of the rectangular tooth, the rectangular tooth is generally used in practical applications. Too large or too small pole tooth width will reduce the sealing ability. For this experiment, more reasonable tooth width is 2-4mm; In a certain range, tooth height has very little effect on sealing pressure.
The two-dimensional heat transfer model of experimental device is established and solved to obtain the temperature field of the shaft, pole and permanent magnet. The numerical results show that the temperature of the magnetic pole close to the cooling water trough is lower than the temperature of the shaft due to the cooling effect of water; the temperature of the inner pole near the Freon is lowest, the minimum temperature is 80℃; the temperature of the permanent magnet is relative lower because of the low thermal conductivity of the air between the rotor and the permanent magnet.
电机中冷却液的密封成为该技术的一个关键点。传统密封装置很难达到要求,针对这种工作环境我们提出采用新型密封技术,即磁脂密封。不同间隙和不同齿形的密封结构会影响磁场分布和密封耐压能力；而转轴和磁极的温度场对密封寿命有至关重要的影响。
本文首先采用ANSYS分析软件,对磁脂密封不同结构的模型进行磁场的数值模拟,通过得出的实际密封简化耐压公式计算该密封的耐压能力,结果表明：磁脂密封能力好于普通磁流体密封,且由于磁脂密封的磁极与转轴间隙可以更大,所以适用于转轴径向跳动量大的场合,应用范围更广泛。研究表明,磁脂密封失效发生在什么位置是与密封间隙有关系的。双斜齿的密封耐压能力稍强,单斜齿次之,矩形齿稍弱；但三种不同齿形的耐压能力相差不大。由于矩形齿加工工艺简单,性能容易保证,因此在实际应用中一般选用矩形齿；极齿宽度太大或太小都会降低密封能力。对于本实验装置,极齿宽度取2-4mm较为合理；在一定范围内,不同的极齿高度对对密封压差影响不大。
建立了实验装置的二维传热模型,并对该模型进行数值求解,获得转轴、磁极和永磁铁内部的温度分布,结果表明：受冷却水的影响,冷却水槽附近磁极温度明显低于转轴的温度；温度最低处发生在与氟利昂接触的内侧磁极,最低温度为80℃；由于转轴与磁铁之间为空气,导热系数低,因此永磁铁的温度较低。
The liquid cooling technology of low boiling point that solved the low speed and high-torque motor cooling is an effective traditional craft of reducing the motor size and improving motor efficiency. The use of this technology can remove the large gear box, greatly optimize the structure design and reduce equipment costs for China's large-scale electrical and petrochemical industries, marine machinery.
Sealing motor cooling fluid is a key point of the technology. The generally traditional seal is difficult to meet the requirements. In view of this working environment, we propose using new sealing technology-the high viscous and non-Newtonian magnetic fluid sealing. Different sealing gap and different tooth structure will affect the magnetic field distribution and sealed pressure capabilities; while the temperature field of shaft and pole have a critical influence on sealing life.
In this paper, high viscous and non-Newtonian magnetic fluid sealing different gap and different tooth structure was analyzed by using the finite element software package ANSYS. The sealing pressure was calculated by the equation of actual pressure resistance, the results show that the seal capacity of the high viscous and non-Newtonian magnetic fluid sealing is better than the ordinary magnetic fluid sealing and the high viscous and non-Newtonian magnetic fluid sealing is applicable to the occasions of large axial-radial pulse volume and has wide range of applications because of the large gap between of the magnetic pole and the shaft. The location of failure has relationship with the seal gap. The seal pressure capability of double-oblique tooth is slightly stronger than single-oblique tooth, and the seal pressure capability of rectangular tooth is weakest, but the seal pressure capability of three different teeth is or less. As machining process simply and easy to guarantee performance of the rectangular tooth, the rectangular tooth is generally used in practical applications. Too large or too small pole tooth width will reduce the sealing ability. For this experiment, more reasonable tooth width is 2-4mm; In a certain range, tooth height has very little effect on sealing pressure.
The two-dimensional heat transfer model of experimental device is established and solved to obtain the temperature field of the shaft, pole and permanent magnet. The numerical results show that the temperature of the magnetic pole close to the cooling water trough is lower than the temperature of the shaft due to the cooling effect of water; the temperature of the inner pole near the Freon is lowest, the minimum temperature is 80℃; the temperature of the permanent magnet is relative lower because of the low thermal conductivity of the air between the rotor and the permanent magnet.
引文
[1]邹继斌,陆永平.磁性流体密封原理与设计[M],北京：国防工业出版社,2000.
[2]王瑞金.磁流体技术的应用与发展[J],新技术新工艺,2001(10).15-18.
[3]蒋秉植,杨健美.磁性液体材料的应用[J],化工新型材料,1994(4).1-5.
[4]黄兴,林原.新世纪密封技术面临的问题及其发展趋势[J],润滑与密封,2002(1).76-78.
[5]刘同冈,杨志伊.磁流体液体动密封结构的优化设计[J].摩擦学学报,2003(04).353-355.
[6]王俊勇,蒋生发.用有限元法合理设计磁流体密封结构[J].排灌机械,1999(01).
[7]陈达畅.磁性流体装置的设计与密封实验结构[D],汕头大学,2005.
[8]张素正,景魏.磁性流体装置主要结构参数的设计及分析[J],机械制造与研究,2007(36).16-17,20.
[9]李保锋,余智勇,刘颖,闫令文.一种磁流体密封装置的实验研究及其改进措施[J],润滑与密封,2004(2).15-19.
[10]王淑珍,李德才.磁流体密封结构的设计与实验研究[J],功能材料,2007(38).1224-1226.
[11]邹继斌,尚静,孙桂瑛.磁流体密封压差的数值计算[J],摩擦学报,2000,20(1).46-49.
[12]Sama M S, Stahl P, Ward A. Magnetic field analysis of ferrofluid Seals for optimum design[J], J Appl Phys.1984,55(6).2595-2597.
[13]孙明礼,李德才,崔海蓉,何新智.磁流体密封的磁场数值分析[J],北京交通大学学报,2008,32(2).116-118.
[14]王瑗,樊玉光,杨勇.用有限元仿真计算法研究纳米磁性流体密封的磁场分布[J],内蒙古石油化工,2006(20).31-34.
[15]张媛,张建斌,邵新杰.磁流体密封的磁场分析[J],润滑与密封,2006(20).31-34.
[16]李国斌,宋顺成,赵宝荣,高平,刘若涛.典型磁流体密封结构磁场有限元分析[J],润滑与密封,2005(1).79-81.
[17]芮菁,顾建明,徐烈.磁性液体密封的实验研究[J],真空与低温,1997,3(2).84-87.
[18]樊玉光,袁淑霞.一种零泄漏密封技术—纳米磁性流体密封研究的进展[J],润滑与密封,2003(2).81-84.
[19]邹继斌,陆永平.旋转轴的磁性流体密封[J],哈尔滨工业大学学报,1991(1).73-79.
[20]邹继斌,陆永平.离心力在旋转轴磁性流体密封中的作用[J],润滑与密封,1990(1).2-4.
[21]顾建明,许永兴,陆明琦,芮菁.磁流体密封间隙对密封性能的影响[J],上海交通大学学报,1999,37(3).380-382.
[22]Zhao Meng, Zou Jibin, Hu Jianhui. An analysis on the magnetic fluid seal capacity[J], Journal of Magnetism and Magnetic Materials,2006,303.428-431.
[23]王之珊,宋立新,甘彦普.转速对铁磁流体动密封能力影响的实验研究[J],1996,22(4). 490-494.
[24]李德才,袁祖贻.磁流体密封的研究,北方交通大学学报[J],1995,19(2).183-187.
[25]Ochonski W. Dynamic sealing with magnetic fluids[J], Wea,1989,130(1).261-268.
[26]郑小荣,杨逢瑜,骆明辉,田力国.磁流体密封压力及动密封粘滞功耗确定[J],石油化工设备[J],2002,31(3).13-15.
[27]Decai Li, Haiping Xu, Xinzhi He, Huiqing Lan. Study on the magnetic fluid sealing for dry Roots pump[J], Journal of Magnetism and Magnetic Materials,2005,289.419-422.
[28]Y.S. Kim, K. Nakatsuka, T. Fujita, T. Atarashi. Application of hydrophilic magnetic fluid to oil seal[J], Journal of Magnetism and Magnetic Materials,1999,201.361-363.
[29]B.萨胡,H.G.沙尔马.均匀自由流动的非牛顿流体中连续表面上的磁流体动力学流动和热传递[J],应用数学与力学,2007,28(11).1307-1317.
[30]王瑞金,曹森龙.磁流体密封的原理和应用[J].通用机械,2005(2).54-58.
[31]倪光正等编著.工程电磁场数值计算[M].北京：机械工业出版社,2004.
[32]盛剑霓等编著.电磁场数值分析[M].北京：科学出版社,1984.
[33]李德才.磁性液体理论及应用[M].北京：科学出版社,2003.
[34]#12
[35]Walowit J. Analysis of Magnetic Fluid Seals. ASLE Transactions,1981,24(4).
[36]Pinkuso. Model Testing of Magnetic Fluid Seals. ASLE Transactions,125(1).79-87.
[37]杨世铭,陶文铨.传热学(第三版)[M],北京：高等教育出版社,1998.
[2]王瑞金.磁流体技术的应用与发展[J],新技术新工艺,2001(10).15-18.
[3]蒋秉植,杨健美.磁性液体材料的应用[J],化工新型材料,1994(4).1-5.
[4]黄兴,林原.新世纪密封技术面临的问题及其发展趋势[J],润滑与密封,2002(1).76-78.
[5]刘同冈,杨志伊.磁流体液体动密封结构的优化设计[J].摩擦学学报,2003(04).353-355.
[6]王俊勇,蒋生发.用有限元法合理设计磁流体密封结构[J].排灌机械,1999(01).
[7]陈达畅.磁性流体装置的设计与密封实验结构[D],汕头大学,2005.
[8]张素正,景魏.磁性流体装置主要结构参数的设计及分析[J],机械制造与研究,2007(36).16-17,20.
[9]李保锋,余智勇,刘颖,闫令文.一种磁流体密封装置的实验研究及其改进措施[J],润滑与密封,2004(2).15-19.
[10]王淑珍,李德才.磁流体密封结构的设计与实验研究[J],功能材料,2007(38).1224-1226.
[11]邹继斌,尚静,孙桂瑛.磁流体密封压差的数值计算[J],摩擦学报,2000,20(1).46-49.
[12]Sama M S, Stahl P, Ward A. Magnetic field analysis of ferrofluid Seals for optimum design[J], J Appl Phys.1984,55(6).2595-2597.
[13]孙明礼,李德才,崔海蓉,何新智.磁流体密封的磁场数值分析[J],北京交通大学学报,2008,32(2).116-118.
[14]王瑗,樊玉光,杨勇.用有限元仿真计算法研究纳米磁性流体密封的磁场分布[J],内蒙古石油化工,2006(20).31-34.
[15]张媛,张建斌,邵新杰.磁流体密封的磁场分析[J],润滑与密封,2006(20).31-34.
[16]李国斌,宋顺成,赵宝荣,高平,刘若涛.典型磁流体密封结构磁场有限元分析[J],润滑与密封,2005(1).79-81.
[17]芮菁,顾建明,徐烈.磁性液体密封的实验研究[J],真空与低温,1997,3(2).84-87.
[18]樊玉光,袁淑霞.一种零泄漏密封技术—纳米磁性流体密封研究的进展[J],润滑与密封,2003(2).81-84.
[19]邹继斌,陆永平.旋转轴的磁性流体密封[J],哈尔滨工业大学学报,1991(1).73-79.
[20]邹继斌,陆永平.离心力在旋转轴磁性流体密封中的作用[J],润滑与密封,1990(1).2-4.
[21]顾建明,许永兴,陆明琦,芮菁.磁流体密封间隙对密封性能的影响[J],上海交通大学学报,1999,37(3).380-382.
[22]Zhao Meng, Zou Jibin, Hu Jianhui. An analysis on the magnetic fluid seal capacity[J], Journal of Magnetism and Magnetic Materials,2006,303.428-431.
[23]王之珊,宋立新,甘彦普.转速对铁磁流体动密封能力影响的实验研究[J],1996,22(4). 490-494.
[24]李德才,袁祖贻.磁流体密封的研究,北方交通大学学报[J],1995,19(2).183-187.
[25]Ochonski W. Dynamic sealing with magnetic fluids[J], Wea,1989,130(1).261-268.
[26]郑小荣,杨逢瑜,骆明辉,田力国.磁流体密封压力及动密封粘滞功耗确定[J],石油化工设备[J],2002,31(3).13-15.
[27]Decai Li, Haiping Xu, Xinzhi He, Huiqing Lan. Study on the magnetic fluid sealing for dry Roots pump[J], Journal of Magnetism and Magnetic Materials,2005,289.419-422.
[28]Y.S. Kim, K. Nakatsuka, T. Fujita, T. Atarashi. Application of hydrophilic magnetic fluid to oil seal[J], Journal of Magnetism and Magnetic Materials,1999,201.361-363.
[29]B.萨胡,H.G.沙尔马.均匀自由流动的非牛顿流体中连续表面上的磁流体动力学流动和热传递[J],应用数学与力学,2007,28(11).1307-1317.
[30]王瑞金,曹森龙.磁流体密封的原理和应用[J].通用机械,2005(2).54-58.
[31]倪光正等编著.工程电磁场数值计算[M].北京：机械工业出版社,2004.
[32]盛剑霓等编著.电磁场数值分析[M].北京：科学出版社,1984.
[33]李德才.磁性液体理论及应用[M].北京：科学出版社,2003.
[34]#12
[35]Walowit J. Analysis of Magnetic Fluid Seals. ASLE Transactions,1981,24(4).
[36]Pinkuso. Model Testing of Magnetic Fluid Seals. ASLE Transactions,125(1).79-87.
[37]杨世铭,陶文铨.传热学(第三版)[M],北京：高等教育出版社,1998.