Lubrication heating behavior of elliptical groove face seals under multi-point conditions

Abstract

With the increasing requirement of multi-point working conditions, the problem of lubrication heat in liquid face seals attracts more attentions, which often results in a high risk of seal failure due to unstable opening force and leakage. The precise design considering heating effect of face grooves under complex working conditions is necessary. Here, based on the fluid lubrication theory, a thermo-dynamic model for liquid face seals with elliptical groove was established to analyze the lubrication heat behavior. The novelty of this model is to take the complex seal structure, cavitation effect and fluid thermo-viscous effect into consideration together, which was validated by experimental work. The temperature distribution and temperature rise were investigated for both smooth and elliptical groove face seals. The effects of rotational speed, film thickness and sealing pressure on temperature distribution and sealing performance of liquid film were further studied. When the film thickness increasing from 2 to 5 μm, the maximum temperature for face seals with elliptical groove and smooth surface decreases from 355.6 K to 350.45 K and from 354.9 K to 350.4 K, respectively. The values of maximum temperature present no obvious difference for both smooth and elliptical faces. However, it is found that elliptical groove presents an obvious influence on temperature distribution of liquid sealing film. The maximum temperature occurs near the inner diameter for the smooth face, but near the outer diameter for the elliptical groove face. The obtained results also suggest that the cavitation effect and hydrodynamic effect induced by shear effect make the sealing performance unstable, accompanying multi-peaks phenomena under multi-velocity and multi-pressure conditions. Face grooves could provide a potential way to control temperature distribution in precise sealing design.