Modeling the valve dynamics in a reciprocating compressor based on two-dimensional computational fluid dynamic numerical simulation

This article presents a numerical simulation of the thermodynamic process in the cylinder and dynamics of the self-acting valves for an air reciprocating compressor. The finite-volume method was employed to solve the compressible turbulent flow in the cylinder and through the valves. A single degree-of-freedom model was adopted to simulate the valve dynamics. The piston’s motion was defined by a user’s preset function, and the fluid-structure interaction between the gas flow and the valve dynamics was solved in a strictly coupled fashion. The technique of non-conformal interfaces was adopted to allow fluxes between adjacent zones with different mesh node locations. Based on the analysis of the characteristics of the flow through valves and the valve movement, sensitivity analysis on the valve impact velocity and the angle of inclination indicates that the valve impact velocity was more sensitive to the variation of the rotational speed and the valve lift while severe inclining motion occurs when the valves are installed in the radial direction. Instantaneous gas flow and force coefficients with the variation of valve displacement are also obtained according to the mass-flow rate across the valve and the gas force acting on the ring plate.

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