Multi-physical field coupled mixed lubrication analysis of hydraulic reciprocating VL Seal

Abstract Engineering practice has demonstrated that seal failure can result in severe leakage and wear, reducing the efficiency of hydraulic systems and even leading to major safety accidents. Currently, there is relatively limited analysis of the thermal aspect of seal interfaces, with most studies focusing on the mechanical analysis. However, in actual applications, temperature has a significant impact on sealing performance. In this paper, nonlinear elastomechanics, viscous fluid mechanics, micro-contact mechanics, micro-deformation theory, and thermodynamics are coupled to establish a mixed lubrication model considering the thermal effect. The reliability of the mixed lubrication model is verified through experiments, and the temperature distribution of the oil film in the sealing area and the temperature distribution of the seal ring are simulated. Finally, the effects of reciprocating speed, root mean square roughness, and seal ring interference on seal friction force and leakage are investigated.The results show that the heat generated in the sealing area accumulates at the bottom of the V-ring. Under the same conditions, compared with the inner stroke, the temperature rise area of the outer stroke is biased to the left and has a higher temperature rise. In addition, the piston rod speed and the interference of the seal ring have a greater impact on the overall seal friction force and leakage, while at a low interference, the root mean square roughness has a significant impact on the outer stroke of the piston rod, but a limited impact on the inner stroke.