Due to the large spindle diameter and high linear speed,the existing magnetic fluid sealing structure is difficult to meet the requirements of installation and heating of large-scale geotechnical centrifuges.A new type of split magnetic fluid sealing device was designed,and the finite element numerical analysis method was used to study the influence of the split structure deformation,the structural parameters of the pole shoe assembly on the sealing performance and the temperature distribution of the sealing device.Considering the actual processing capacity,orthogonal experiments were used to optimize the structural parameters.The results show that the degree of influence of structural parameters on sealing performance is as follows,the sealing clearance,the permanent magnet height,the permanent magnet width,the slot width,the tooth width,and the tooth height.The parameters of the optimized sealing device are sealing gap 0.5 mm,tooth width 2 mm,tooth height 2 mm,slot width 2.8 mm,permanent magnet width 11 mm,and permanent magnet height 22 mm.The optimized sealing pressure value is 0.97 MPa,which is higher than the pressure value of 0.54 MPa before optimization,and higher than the pressure value of 0.1 MPa required by the operating conditions.During the operation of the large diameter magnetic fluid seal,there is a problem of heat accumulation in the shaft sleeve,and a cooling chamber needs to be set up in the shaft sleeve area.