An experimental/theoretical study of contact phenomena in mechanical face seals

Mechanical face seals are assumed to operate with a uniform, thin film of sealed fluid between the flat, parallel seal faces. Recent evidence has indicated, however, that in many seals there exist patches of solid-to-solid contact between the seal faces. The temperatures and stresses near these concentrated contacts may be responsible for some modes of seal failure. In this study an experimental determination was made of the number, size, and location of contact patches in an operating face seal. This information was used in a numerical analysis, using finite element techniques, of temperatures, deformations, and stresses around the contact patches. An independent experimental measurement of surface temperature profile within the contact patches was used to refine the numerical analysis and to enable determination of frictional heat flux and contact pressure distributions. The results of the study give insight into the factors affecting modes of seal failure, such as thermocracking.