[2J06-09] Gas-Liquid Two-Phase Flow 2

[2J06] Measurement of Boiling Entrainment Rate from a Liquid Film Flowing Downwards on a Vertical Heated Surface

*Raka Firman Baskara Permana¹, Tomio Okawa¹, Yuki Narushima², Hajime Furuichi², Kenichi Katono² (1. UEC, 2. Hitachi)

Keywords:Annular Two-Phase Flow, Boiling Entrainment Rate, CHF, Dryout

Boiling entrainment in annular two-phase flow is associated with the occurrence of the liquid film dryout in the annular two-phase flow. Therefore, experiments to measure the boiling entrainment rate were carried out from a liquid film flowing downwards on a vertical heated surface. In the experiments, droplet capturing device was used to collect and measure the produced boiling entrainment. It was found that the boiling entrainment rate was negligible when the wall heat flux was low and it increased as the wall heat flux increased. The experimental results tended to be consistent with the existing Ueda et al.'s model. However, the discrepancy was noticeable at the relatively high heat flux more than the critical condition. It was because of the difference in the heating length which affected the amount of the occurrence of nucleate boiling and thus, the amount of boiling entrainment rate.