A Non-Axisymmetric Steady State Model of a Mechanical Seal for Down-Hole Tools

A non-axisymmetric steady state numerical model has been developed for use in the design of mechanical seals for down-hole tools. It is applicable to other types of mechanical seals in which friction from the static secondary seal is significant, as well. This model predicts such quantities as leakage rate, external fluid incursion rate, film thickness distribution, fluid pressure and contact pressure distributions, interface temperature and face deformation. Model results show that for a given set of operating conditions, there is a range of equilibrium states of the seal, corresponding to a range of inclinations of the non-rotating seal face relative to the rotating face. Depending on the inclination, it is possible to have negative leakage due to the asymmetry of the film thickness distribution. Even with positive leakage, under some circumstances incursion of the external fluid can occur as a result of the asymmetry.