Static Sealing Performance of Gas Mechanical Seals Including Surface Roughness and Rarefaction Effects

Abstract

The combined problems of contacting rough surfaces and pressure-induced flow in their interface are formulated and solved. The analysis is valid for thin gas films, where rarefaction effects are significant. The effects of the face loading surface roughness, material properties and operating conditions on the static sealing performance of mechanical gas seals are investigated. It is found that, as the surface roughness and the Knudsen number increase, the leakage also increases. For very low leakages, corresponding to high face loading the effect of the Knudsen number on the leakage is still significant but the effect of the surface roughness diminishes. A semi-empirical model that relates the leakage with the face loading and the other relevant parameters is developed. This model favorably compares with available experimental data and provides a simple tool for evaluating static sealing performance of mechanical gas seals.

Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998

KEY WORDS:

• Gas Seals
• Flow Rate
• Contact of Rough Surfaces

Notes

Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998