Performance analysis of a suction muffler in a hermetic reciprocating compressor using CAA techniques based on Lattice Boltzmann Method

A suction muffler in a hermetic reciprocating compressor is used for reducing noise induced by pressure pulsation inside the compression chamber. Since complex flow passages inside the suction muffler inevitably lead to the adverse effects on the efficiency of the compressor, high-performance mufflers in terms of both flow and acoustics are favored. However, the acoustic and flow performances of the muffler are still separately assessed in terms of the insertion loss and pressure drop in the related industry. In fact, flow and acoustic waves inside the muffler interacts strongly so that the separate prediction cannot provide the reliable assessment for each performance. In this paper, acoustic and flow performances of a suction muffler used in a reciprocating compressor is numerically investigated using the computational aeroacoustic (CAA) techniques based on the Lattice Boltzmann Method, which solves flow and acoustics simultaneously. To improve the accuracy of numerical simulation results, the measured static pressure at the inlet of the compression chamber is used at the outlet boundary condition. The energy conversion between the acoustic and vorticity waves are identified, which manifests that the interactions between the flow and acoustic quantities play important roles in determining the acoustic and flow performances of a muffler. The identified physical phenomena can be used to provide new design concepts to maximize the flow rate while keeping the noise level at a minimum.