High temperature will reduce the saturation magnetization strength of the magnetic fluid and cause demagnetization of the permanent magnet,which affects the reliability and stability of the magnetic fluid seal device.In order to explore the heat transfer characteristics of the magnetic fluid seal device,the magnetic fluid seal of large shaft diameter centrifugal compressor was used as the research object,the influence of magnetic fluid friction heat and bearing friction heat on the heat transfer characteristics of magnetic fluid sealing devices was considered simultaneously,and the method of combining finite element numerical calculation with theoretical analysis of magnetic fluid and bearing frictional power consumption was used to study the temperature distribution law of the seal device.The effect of tooth width,seal gap and rotational speed on the maximum steady-state temperature of permanent magnet and magnetic fluid was analyzed,and the required coolant mass flow rate for relevant working conditions was determined.The results show that due to the large shaft diameter and high surface linear velocity of the centrifugal compressor,the viscous frictional heat of the magnetic fluid and the frictional heat of the bearing have a significant effect on the heat transfer characteristics of the seal device.The maximum temperature of the seal device exceeds the ultimate operating temperature of the magnetic fluid and the permanent magnet under the non-cooling condition,and cooling treatment needs to be carried out through convection heat transfer.The maximum steady-state temperature of the permanent magnet and magnetic fluid increases with the increase of tooth width,and decreases with the increase of seal gap.The maximum steady-state temperature of the permanent magnet and magnetic fluid increases with increase of rotational speed,and the higher the speed,the greater the temperature difference between the same speed gradient.