Design And Experimental Study Of Magnetorheological Fluid Seal Structure

Sodium-cooled fast reactor is a common type of fourth generation advanced nuclear power system.It uses liquid sodium as coolant.The liquid sodium coolant is usually covered by inert gas argon to protect it.Therefore,the sealing medium is sodium vapor covered by argon.At present,the main shaft seal of sodium reactor is mechanical seal,but there are some shortcomings,such as poor sealing performance,complex structure and difficult maintenance.Previously,the magnetic fluid seal applied to the spindle of sodium reactor was studied,but the sealing clearance of the magnetic fluid seal is small,and the processing accuracy is high.When the sealing clearance increases,the pressure resistance of the magnetic fluid seal decreases greatly.Magnetorheological fluids(MRF)and magnetic fluids are similar in composition.They not only have the magnetism of magnetic fluids,but also produce greater yield stress under the action of external magnetic field.Compared with magnetic fluid seals,MRF seals have the advantages of high pressure resistance,less sealing series,large sealing clearance and low processing accuracy requirements.Therefore,according to the design of the main shaft system of sodium reactor,the MRF sealing device is designed,and its simulation analysis and experimental research are carried out.The main research contents are as follows:(1)Based on the magnetization pressure and yield stress of MRF seal under the action of magnetic field,the formula for calculating the pressure resistance of MRF seal is obtained.(2)Based on the sealing performance requirements of the sodium reactor spindle system,the design scheme of MRF sealing device is proposed,and the key components of MRF sealing structure are designed.(3)Through ANSYS software simulation,the pressure resistance of MRF seal structure was analyzed and calculated.The effects of seal clearance,tooth width and tooth height of polar teeth and thickness of permanent magnet on the pressure resistance of MRF seal were studied.(4)A sealing test bench was set up to study the sealing performance of the assembled MRF sealing device.The effects of different sealing clearances,polar tooth width,initial pressure and rotational speed on the sealing performance of MRF were studied,and the pressure variation law between the sealing chamber and the pole shoe was obtained.It provides a theoretical and experimental basis for the application of magnetorheological fluids in sealing.