An eccentric 3-D fluid-structure interaction model for investigating the effects of rod parallel offset on reciprocating-seal performance

The rod parallel offset ruins the axial symmetry of reciprocating seals, making the traditional 2-D model inappropriate for quantitative analysis. We propose an eccentric 3-D fluid-structure interaction (FSI) model, comprising the parallel-offset and mixed-lubrication sub-models to investigate the influence of parallel offset on the seal's micro- and macro-performance. Details of the sealing zone, friction and leakage features are analyzed for an O-ring seal at different eccentric distances, system pressures and velocities. Comparisons between the friction characteristics in the mixed-lubrication and dry conditions are also implemented in this paper. •An eccentric 3-D FSI model is proposed to analyze the effect of parallel offset.•The impact of parallel offset on the friction force is limited.•The parallel offset increases the net leakage.•The hydrodynamic effect in the mixed lubrication could enhance friction difference.•The increasing velocity decreases both the friction force and friction difference.