Measurement of Oil Film Thickness for Application to Elastomeric Stirling Engine Rod Seals

Abstract

This paper describes an experimental program concerned with the elasto-hydrodynamic behavior of sliding elastomeric seals for the Stirling engine. During this program, an experimental apparatus was designed, built, and used to measure the oil film thickness distribution. For this oil film thickness measurement, an optical interferometric procedure was developed. Tests were conducted on commercial elastomeric seals having a 76 mm o.d. Testing conditions included seal durometers of 70 and 90, a sliding velocity of 0.8 m/s, and no pressure gradient across the seal. An acrylic cylinder and a typical synthetic base automotive lubricant were used. The work produced a first-time comparison of analytical and experimental oil film profiles for an elastomeric seal in a reciprocating environment. This comparison shows an overall qualitative agreement.