Numerical Study Of Magnetic Field And Heat In High Viscous And Non-Newtonian Magnetic Fluid Sealing

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.