Macroscopic friction leakage and microscopic seepage characteristics of Glyd rings as wear process

Abstract

Wear and microscopic seepage will be aggravated when reciprocating combined seals used with high water-based liquid owing to its low viscosity and strong permeability. To accurately evaluate the tribological and seepage properties of the combined seal under the high water-based liquid, considering wear and microscopic seepage, a macroscopic friction and leakage model of the Glyd ring is constructed based on the mixed lubrication and film thickness corrected Archard theory, a seepage analysis method based on the two-dimensional Reynolds equation for the microchannel is further proposed by integrating the actual microscopic morphology and macroscopic compression ratio. The friction force and wear thickness tests are carried out for verification. The result shows that the Glyd ring undergoes with a decrease in the amplitude of rough peaks and valleys, characterized by an expansion of the microscopic contact area and a decrease in seepage channel height. The reduction in friction force as wear continues is caused by the combined effects of decreased pre-compression and micro-convex peaks. The traditional Archard model, based on the contact pressure of micro-convex bodies, will overestimate the wear amount. Introducing a lubrication correction coefficient related to film thickness can improve the accuracy of wear assessment. The microscopic seepage of the Glyd ring is approximately 1/130 of the macroscopic leakage, and it will continue to decrease as the wear process. The research results provide a theoretical basis for accurately predicting the leakage and wear characteristics of the Glyd ring and other reciprocating seals.