Liu, Z., Wozniak, D., Koberstein, M., Jones, C. et al., "Flow-Induced Gurgling Noise in Automotive Refrigerant Systems," SAE Int. J. Passeng. Cars - Mech. Syst. 8(3):977-981, 2015, doi:10.4271/2015-01-2276.
Refrigerant flow-induced gurgling noise is perceived in automotive refrigerant systems. In this study, the condition of the gurgling generation is investigated at the vehicle level and the fundamental root cause is identified as the two-phase refrigerant flow entering the TXV for system equipped with variable displacement compressors. By conducting literature reviews, the acoustic characteristics of the flow patterns and the parameters affecting the flow regimes in horizontal and vertical tubes are summarized. Then the gurgling mechanism is explained as the intermittent flow is developed at the evaporator inlet. In the end, the improved and feasible design for avoiding the intermittent flow (slug, plug or churn flow) or minimizing its formation is proposed and verified in refrigerant subsystem (RSS) level. Finally, the guidelines for the attenuation and suppression of the gurgle are provided.