Tuning the sound characteristics of flow-induced noise generated in a refrigeration system

Refrigeration equipment is extensively utilized in residential, commercial and industrial applications, but the issue of flow-induced noise problems remains a tragic problem. The jet flow noises generated by refrigerants have drawn considerable attentions in noise control engineering to mitigate acoustic instability. The jet flow and phase transition in mufflers can lead to flow separation and vortex shedding, resulting in a substantial decrease in acoustic attenuation performances. In this work, the acoustic attenuation performances of a novel acoustic muffler used at the junction between capillary and evaporator were systematically investigated. The proposed acoustic muffler can weaken the jet flow noise by damping the vortices and flow oscillations with an enhanced design, which exhibits superior attenuation performances with the jet flow Mach Number from 0 to 0.15. Compared to the multi-stage pipes under the identical operating condition, the sound pressure level of the improved acoustic muffler exhibits a reduction of average 10 dBA within the frequency range of 1000 Hz to 4500Hz. The results show outstanding noise-attenuation performance and may inspire the development of highly efficient and broadband acoustic mufflers for weakening the jet flow noise in refrigeration systems.