Internal flow field and operational efficiency evaluation model of hydraulic cylinder considering inlet pressure and clearance impacts.

This article focuses on evaluating the coupled effects of inlet pressure and radial clearance on the operational efficiency of hydraulic cylinders through a combined approach of computational fluid dynamics (CFD) simulation using dynamic mesh technology and an empirical efficiency model. The study reveals that at high inlet pressure (2 MPa), an optimal radial clearance of 0.75 mm maximizes efficiency by balancing leakage and shear losses, improving energy utilization by about 5%, whereas exceeding this clearance sharply increases leakage and reduces efficiency. At low pressure (1 MPa), leakage dominates energy loss, and changes in clearance have minimal impact on efficiency. The research establishes that pressure and velocity gradients within the oil film jointly influence system response speed, stability, and energy consumption, with narrow clearances yielding faster response but higher energy loss, and moderate clearances enhancing stability and efficiency. The proposed empirical model effectively predicts hydraulic cylinder performance across varying operating conditions, providing theoretical support for optimizing hydraulic system design.