expansion device, noise-prediction model, synched high-speed measurements, flow regimes
The flow-induced noise near the expansion device can be very disturbing to users. Studies related to the relationship between the flow-induced noise and flow regimes are calling more and more attention in recent decades. However, current studies lack a quantitative relationship between flow characteristics and the flow-induced noise. Therefore, in this paper, a noise-prediction model is proposed to predict the sound pressure level of flow-induced noise. The paper utilizes a pumped R134a loop with a needle valve for synchronized measurements between flow-induced noise and flow regimes. Synchronized high-speed measurements obtained from a microphone and a high-speed camera enable simultaneous investigation of flow-induced noise and flow regimes. Both the experimental results and the modeling results show that the sound pressure level of gurgling noise increases as the flow quality increases or the system mass flux increases. The relative error of the model for most prediction of flow-induced noise is less than 15%. However, in some high-quality cases, such as annular flow-induced noise, the prediction does not predict the noise well.