In order to study the sealing characteristics of variable section sealing ring under different working conditions and the relationship between lubricating oil film temperature field and viscosity-temperature characteristics,according to the sealing mechanism of the variable section sealing ring,a three-dimensional numerical calculation model of lubricating oil film was established.Considering the viscosity-temperature characteristics and the internal friction effect of the fluid,the sealing characteristics and temperature characteristics of the lubricating oil film of the variable section sealing ring under actual working conditions were studied by using FLUENT and MATLAB software.The results show that there is a significant difference between the results obtained considering the viscosity-temperature characteristics and those obtained under constant viscosity conditions,indicating that the influence of viscosity-temperature characteristics on sealing characteristics cannot be ignored.The highest temperature area of the oil film is located on the external environment side and moves with the change of working conditions.The maximum temperature value of the oil film increases with the increase of the rotational speed,and decreases with the increase of the sealing pressure,but the influence of the rotational speed is greater than that of the other parameters.With the increase of lubricating oil temperature,the maximum temperature value of oil film increases when the viscosity-temperature characteristics are considered,however,when the viscosity is constant,it shows a trend of first decrease and then increase.The leakage increases with the increase of rotational speed,seal pressure and lubricating oil temperature,but the seal pressure has the greatest influence.