Numerical Simulation of a Suction Valve: Comparison between a 3D Complete Model and a 1D Model
Compressor, Suction Valve, Numerical Simulation, 3D Model, 1D Model
Hermetic reciprocating compressors are widely used in small and medium size vapor compression refrigeration systems. One of the main parts of this type of compressor is the automatic valve system used to control the suction and discharge processes. As the opening and closing of the valves are caused by the forces produced by the refrigerant flow itself, the understanding of this fluid-structure interaction problem which characterizes the system dynamics is of fundamental importance in order to enhance the efficiency of the valve system. The numerical simulation of the flow has been used as an efficient method to perform this task. Most of the researchers simulated this problem by considering whether a geometric simplification for the valve (radial diffuser) or a simplification for the dynamics of the structure (one degree of freedom). In order to overcome these two drawbacks, in this work we simulate numerically the fluid structure interaction problem in a real geometry usually used in suction valves by considering a 3D complete model for both the flow and the dynamics of the structure. The Ansys CFX CFD-Computational Fluid Dynamics software was used for the simulation of the flow coupled with the structure module available in the Ansys Mechanical. In addition, a 1D model (one degree of freedom) was also implemented for simulating the dynamics of the structure for comparison reasons. The models were validated against experimental data for the aperture of the valve. We show that the 1D model saves small computational time and provides good results for general characteristics of the problem as the force acting on the valve and the aperture of the valve, while the 3D complete model allows us to predict the deformation of the structure. We suggest the use of the 3D complete model because the computational time is not significantly increased.