A finite element solution of the Reynolds equation of lubrication with film discontinuities: application to helical groove seals

Helical groove seal, is one of the very few non-contact seals that have the capability to effectively seal a liquid. It finds use mainly in turbines and compressors. Although its reliability, this type of seals has not been investigated thoroughly because of its complex characteristics. This work presents a numerical analysis of a helical groove seal operating in laminar regime by means of solving the Reynolds equations for incompressible fluid film in steady state. Equations governing the fluid flow were solved by the finite element method. Although the simplifying assumptions of Reynolds model help to keep the computational time at an acceptable level, the inertia effects are neglected which may lead to unreliable results especially where the film thickness is discontinuous. The present approach, inspired by Arghir et al. [1] is able to take into account concentrated inertia effects, as described by a generalized Bernoulli equation. Comparisons made with the classical Reynolds model show that the film discontinuities should be taken into account when dealing with helically grooved seals. In addition, the leakage of fluid towards the air side was investigated for different parameters such as the groove angle and depth. (paper)