The objective of this project is to determine the effects of shaft surface microgeometry on lip seal operation, through an understanding of the basic physics of lip seal operation. This project is part of a larger international program involving researchers in Poland, Lithuania and Germany. The European groups will be doing experimental studies, while this project will be theoretical. The results of this project will be compared with the experimental measurements.
The initial stage of the the project will consist of a static contact mechanics and deformation analysis of the lip against the various shaft microgeometries, using conventional finite element techniques. This will yield the static pattern of cavities and contact regions between the lip and shaft, and reveal which microgeometries are most efficient in retaining liquid for subsequent formation of the lubricating film.
The second phase will concentrate on determining the effects of the shaft microgeometry on the fluid mechanics of the lubricating film. This will be done through the solution of the Reynolds equation for various lip and shaft microgeometries.
In the third phase, the analysis of phase ii will be combined with a deformation analysis of the lip to yield an elastohydrodynamic model of the seal under full film lubrication conditions. This will allow prediction of the effects of shaft surface microgeometry on the steady-state operation of the seal.
In the fourth stage, the elastohydrodynamic analysis of stage iii will be combined with a contact mechanics analysis to yield a mixed lubrication model, which takes account of the asperity contact between the lip and the shaft. This will allow simulation of lip seal behavior at low speeds. The mixed lubrication model will be used in conjunction with the results of phase i to examine the effects of shaft surface microgeometry on the startup and shutdown processes. ***
