Considering the Lubrication Performance Analysis of Mechanical Seals under the Thermal Deformation of the Dynamic Ring

Mechanical seal is a common sealing device in fluid machinery, among them, the spiral groove mechanical seal with fluid dynamic pressure effect as the most common non-contact seal has the advantages of small end face wear, reliable structure, adaptability, able to withstand a certain degree of temperature change, long service life, etc., and has been more widely used in various fields, including rocket engine turbine pumps, nuclear power plant cooling pumps, and upstream pumping equipment. As the working conditions change to high temperature and high pressure, the pumps have been widely used in various fields. With the development of working conditions to high temperature, high pressure, high speed and other high parameters, the design of the dynamic pressure mechanical seal has put forward higher requirements. The thermal deformation of the spiral groove on the dynamic ring surface of the turbine pump spiral groove dynamic mechanical seal was studied. Firstly, the working conditions of the turbine pump dynamic ring were analyzed, and the thermal deformation of the dynamic ring was analyzed in detail by using finite element simulation technology. On the basis of the thermal deformation analysis of the end face of the moving ring, the deformation of the spiral groove on the surface of the moving ring was quantified, which was divided into the deformation of the groove depth, the deformation of the groove width and the deformation of the spiral angle. Afterwards, a calculation model of the dynamic pressure mechanical seal performance under the thermal deformation of the spiral groove was established based on the traditional Reynolds lubrication equation, etc., and the correctness of the model was verified by comparing it with the theoretical results and literature data. Finally, the model was used to analyze the effects of different spiral groove geometrical parameters on the lubrication properties, such as opening force, leakage and film thickness under the influence of thermal deformation of the spiral groove dynamic ring. The results showed that the changes of groove depth, groove width and helix angle due to the thermal deformation of the moving ring would lead to different degrees of increase in opening force, leakage and film thickness, among which the deformation of groove width and helix angle had less influence on the lubrication performance of the mechanical seals, and the deformation of groove depth had a greater influence on the lubrication performance of the mechanical seals, with a rotational speed of 40 000 r/min and a deformation of groove depth of 3 μm compared with that when the deformation was not taken into account. Opening force, leakage and film thickness changed by 48.1%, 83.3% and 59.0%, respectively, which showed that the influence of deformation could not be ignored. Through the thermal deformation analysis of the spiral groove size changes, and according to these changes in the seal performance analysis, it could provide an important reference for the design of mechanical seals.