Experimental Study on Measurement of Boiling Entrainment Rate From Falling Liquid Film With Gas Sheared Flow

Study on the droplet entrainment in annular two-phase flow has attracted many researchers in connection with the liquid film dryout in the annular two-phase flow. However, the knowledge on the entrainment due to nucleate boiling is still insufficient to predict the droplet entrainment rate accurately. In this study, measurements were made of the droplet entrainment rate with falling liquid films on the locally heated test section. The visualization using a high-speed camera to clarify the accuracy of the measurement results also carried out in this experiment. For the first step in this study, the measurement of the droplet entrainment rate was performed after getting a stable or steady state conditions. Then, we investigated the influence of the separator position on the reproducibility of the droplet entrainment rate to get the droplet entrainment rate – separator position map. As a result, the reproducibility of the droplet entrainment rate increases with decreasing separation distance from the liquid film. In additions, we also investigated the influence of the heat flux and liquid film flow rate on the reproducibility of the droplet entrainment rate. As a result, the reproducibility of the droplet entrainment rate increases with increasing the heat flux and liquid film flow rate. In the future, we expect to investigate the influence of gas flow rate, and degree of subcooling on the reproducibility of the droplet entrainment rate and some correlation models are developed.