Modelling of Reverse Flows in a Mechanical Seal

The present paper describes a two-phase flow model used to study backward pumping of the low pressure fluid in the sealing interface of a mechanical seal. The Reynolds equation for a homogeneous mixture is solved as well as a transport equation used to determine the ratio of both fluids at each point. Several examples are presented to show that the second function of a seal (prevent the contamination of the process fluid by the operating environment) is not always insured because of possible reverse flows. The behavior of the seal can be greatly affected when it is partially lubricated by the low pressure fluid