Investigation of flow and acoustic performances of suction mufflers in hermetic reciprocating compressor

• The flow and acoustic performances of a suction muffler for a compressor are investigated.
• The 3-D compressible RANS equations are solved by using high-order numerical schemes.
• The prediction results of the performances closely follow those of measurements.
• A new muffler proposed for better performances is validated experimentally.

A suction muffler is frequently used to control noise generated by impulsive pressure fluctuation induced by the piston/valve in a reciprocating compressor. However, the suction muffler adversely affects the compressor performance because it causes an additional pressure drop and heat transfer. In this study, with the aim of considering the complex interaction between acoustic waves and flow, both the flow performance and the acoustic performance of a suction muffler are simultaneously investigated by solving three-dimensional compressible Reynolds-averaged Navier–Stokes equations with high-order computational aeroacoustics schemes. To confirm the validity of the proposed numerical scheme for the simulation of acoustic waves, the transmission loss of a simple expansion muffler is predicted and compared with theoretical and experimental results. Then, performances of the target suction muffler are predicted and analyzed. On the basis of the analysis results, a new muffler is designed and its performances are predicted and compared with those of the original one. Finally, validation experiments are performed, whose results confirm improvements in the flow and acoustic performances of the new muffler design.