Analysis of the transient behavior of rotary lip seals : Fluid mechanics and bulk deformation

A numerical model of the transient behavior of rotary lip seals has been developed. It includes a fluid mechanics analysis of the lubricating film, an elastic deformation analysis of the lip, and predicts the lip seal state at every instant of time during a transient in shaft speed. The lip seal state includes such quantities as the lubricating film thickness distribution, pressure distribution, location of cavitation regions, location of the meniscus, and volumetric flow rate of fluid through the lubricating film. When applied to a successful lip seal design, the model predicts that the lubricating film will be formed very rapidly during startup and will be maintained until the very end of the transient during shutdown, thereby minimizing wear of the lip.