Flow-Induced Gurgling Noise in Automotive Refrigerant Systems

Toward the Acoustic Detection of Two‐Phase Flow Patterns and Helmholtz Resonators in Englacial Drainage Systems

“…However, there are few data on the acoustic features and mechanisms of the flow‐induced pulsating sounds identified here. Liu et al () have noted that a similar noise type is most likely to emerge in a vertical flow regime due to intermittent flow and is referred to as “gurgling noise.” The transition from stratified flow to a noise‐generating flow pattern in a pipe depends on the gas/liquid flow rates and conduit geometry and may develop in a horizontal conduit due to the Kelvin‐Helmholtz instability, but this transition usually takes place when the conduit becomes vertical. The air bubble, which has a radius almost equal to the radius of the conduit, must leave through the bottleneck against the downward flow in this configuration to compensate the overpressure from the water entering the unvented drain (Figure a).…”

Evaluation of flow-induced noise, structure vibration, and flow morphology of R134a flowing through a thermostatic expansion valve

“…At this condition, for horizontal layout, the outlet two-phase flow assumes intermittent pattern while the outlet for vertical layout is annular. On the other hand, Liu et al (2015) pointed out the advantageous combination of inclined and horizontal tubes over the vertical layout between the TXV outlet and the evaporator inlet connection, helping to reduce the flow-induced noise, mainly at the frequency range from 1.8 kHz to 6.5 kHz. Analogous to Han et al (2010) and , Liu et al (2015) claim that such an approach may change the evaporator inlet flow pattern from intermittent to stratified or annular flows, diminishing flow-induced noise.…”

“…On the other hand, Liu et al (2015) pointed out the advantageous combination of inclined and horizontal tubes over the vertical layout between the TXV outlet and the evaporator inlet connection, helping to reduce the flow-induced noise, mainly at the frequency range from 1.8 kHz to 6.5 kHz. Analogous to Han et al (2010) and , Liu et al (2015) claim that such an approach may change the evaporator inlet flow pattern from intermittent to stratified or annular flows, diminishing flow-induced noise. According to Han, Jeong and Kim (2011), the collapsing bubble flowing through orifice produces noise at natural frequency band near the natural frequency given by the model of Minnaert (1933) with bubbles having the same diameter as the internal diameter of the orifice .…”