Transient Experimental and 3D-FSI Investigation of Flapper Valve Dynamics for Refrigerant Compressors

The design of the valves for refrigerant compressors has a distinct influence on the efficiency of the refrigeration cycle. In order to predict the valve behavior for compressor optimization, flow characteristics and valve system dynamics are key factors. State of the art valve model approaches have to date ignored the retainer deflection and the influence of contact effects on fluid-structure interaction behavior. With this fact in mind, experimental valve lift investigations by means of laser vibrometry measurements were performed. In order to determine dynamic flapper valve characteristics, oscillation frequency analyses and numerical natural frequency analyses for free oscillation of the flapper valve were carried out. Additionally this paper presents an extended three-dimensional numerical discharge valve model containing a fully-coupled fluid-structure interaction (FSI) approach. The two-way mechanical coupling is carried out by a commercial CFD code combined with a commercial FEA package. The numerical results are validated using the presented experimental transient results and compared to a lumped 1D valve model. The numerical 3D-FSI results show good agreement with the experimental results and allow for further investigations of multiphysics phenomena such as adhesive effects on the flapper valve