Year of Publication

2009

Degree Name

Master of Science in Mechanical Engineering (MSME)

Document Type

Thesis

College

Engineering

Department

Mechanical Engineering

First Advisor

Dr. L. Scott Stephens

Abstract

Previous experimental and theoretical results indicate that the keys to successful radial lip seals are the surface characteristics of the shaft and the microasperity pattern that develops due to wear on the elastomer. In this study, the lip seal was tested against five different patterns of shaft surface: plain stainless steel, triangular cavities oriented towards air, triangular cavities oriented towards oil, triangular cavities leading and triangular cavities lagging. Using Zygo optical profilometer and scanning electron microscope, a thorough surface characterization of the micro-asperities and microcavities is done on the lip seal elastomer. Correlation coefficients were calculated between the surface parameters of the final shaft surface and elastomer. Although both the surface characteristics of the shaft and the micro-asperities that develop on the elastomer sealing zone are responsible for a successful operation of the lip seal, the deterministic triangular micro-cavity patterns created on the shaft surface dominated the pumping direction with a large variability in the pumping rate. This variability is due to the elastomer wear in. This study also finds a significant correlation between the axial position of minimum roughness on the sealing zone of the elastomer and the pumping rate of the lip seals.

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