Simulation of the Effects of a Plunge Ground Rod on Hydraulic Rod Seal Behavior

Abstract

A numerical analysis of a reciprocating hydraulic rod seal with a plunge ground rod has been performed. It consists of coupled fluid mechanics, contact mechanics, and deformation analyses. The fluid mechanics analysis consists of a finite volume solution of the Reynolds equation. The deformation is computed with a finite element analysis. The contact of the seal asperities with the rod utilizes the Greenwood-Williamson model and the rod surface geometry is treated deterministically. The fluid transport, friction force, contact pressure distribution, and fluid pressure distribution in the sealing zone have been computed for a polyurethane U-cup seal and for a step seal with a polytetrafluoroethylene (PTFE) sealing element and a nitrile energizer. These have been compared with the results for a smooth rod.

KEY WORDS:

• Seals
• Elastomeric Seals
• Lip Seals
• Reciprocating Seals
• Rod Seals
• EHL

ACKNOWLEDGEMENTS

The authors gratefully acknowledge the financial support of the National Science Foundation, Engineering Research Center for Compact and Efficient Fluid Power, and the Georgia Power Company.

Review led by Alan Lebeck