NUMERICAL AND EXPERIMENTAL INVESTIGATION INTO FLOW AND ACOUSTIC PERFORMANCES OF MUFFLERS FOR A HERMETIC RECIPROCATING COMPRESSOR

In developing a hermetic reciprocating compressor, highly impulsive pressure fluctuation induced by a reciprocating piston causes noise and vibration problems to be one of the most serious challenges engineers cannot help facing. A muffler is frequently used to control these problems, but also inevitably has adverse effects on performance of a compressor by additional pressure drop and heat transfer of refrigerant. However, complex interactions between acoustic, vortical and entropy waves inside a muffler require the flow and acoustic performances of the muffler to be considered simultaneously. Therefore, in this study, both of flow and acoustic performances of mufflers are investigated by using full three-dimensional compressible Reynolds-Averaged Navier-Stokes computations based on computational fluid dynamics techniques which can account for these interactions. On a basis of the analysis results, new design is introduced, and its performances are compared to the original one. Finally, the flow and acoustic experiments confirms the improved flow and acoustic performances of the proposed design, which in turn ensures validity of applied numerical methods.