Numerical and Experimental Study of Reciprocating Seals in Seawater Hydraulic Variable Ballast Components for 11,000-m Operation.

The seawater hydraulic variable ballast system (SHVBS) is critical equipment for underwater operations. Reciprocating seals play a vital role in the efficiency and safety of seawater hydraulic components working in SHVBS. However, the sealing performance and friction behavior of reciprocating seals remain unknown under high isostatic and water-lubricating conditions. In this work, an innovative mixed lubrication model for reciprocating water hydraulic rod seals is developed based on the elastohydrodynamic lubrication (EHL) theory. An elastic deformation method is introduced to update the film thickness rapidly. The characteristics of the reciprocating seal are studied in a full-ocean-depth pressure range. With the rod speed of 500 mm/s, for sealed pressure of 0.1 MPa and 120 MPa, the maximum friction force increases 10-fold, from about 30 N to 300 N. A test rig is designed to measure friction force under high pressure. The numerical and experimental results have the same variation pattern, and the relative error is less than 15%. [ABSTRACT FROM AUTHOR]