The calculation of pressure distorsion coefficient of pressure balance 500 MPA by using a finite element method

This paper describes a method to calculate the pressure distortion coefficient ( λ ) of 500 MPa, free deformation (FD), oil piston-cylinder unit (PCU) by using the fluid flow and structure problem. The fluid flow is analyzed in the piston-cylinder clearance employing an analytical method on the basis of the Navier-Stokes equation. The piston and cylinder radius distortions are determined as the axisymmetric model through the finite element methods (FEM) structural analysis. The ideal mean gap width between the piston and the cylinder is obtained after measuring the piston fall rate while the effective area of the piston-cylinder is obtained from the cross-float experiment with another piston gauge. The material properties such as Young's modulus and Poisson's ratio have been taken from the manufacturer. The fluid density and dynamic viscosity are assessed from the experimental analysis of the Di-2-Ethyl-Hexyl-Sebacate. The pressure distortion coefficient and its uncertainty are presented.