The Mechanism of High Fluid Pressure Differential on the Sealing Performance of Rotary Lip Seals

Abstract

This study develops a mixed thermal lubrication model incorporating fluid-solid-thermal-contact multiphysics coupling effects, enabling precise quantification of reverse pumping rate and friction torque characteristics in rotary lip seals. The results demonstrate that the reverse pumping rate increases with rotary speed, consistent with classical reverse pumping mechanism. However, under increasing fluid pressure differential, the pumping rate exhibits an "increase-decrease-increase" trend, which cannot be explained by classical reverse pumping mechanism. Mechanistic analysis reveals that this phenomenon originates from the competitive interaction between pressure flow and shear flow. These findings supplement classical reverse pumping theory and provide critical theoretical guidance for the design and optimization of rotary lip seals.

Keywords: rotary lip seal, mixed thermal lubrication, high fluid pressure differential