[2F01-04] Gas-Liquid Two-Phase Flow

[2F02] Interfacial Friction in Vertical Pipes under Countercurrent Flows

(2)Flooding at the Top End

*Michio Murase¹, Toshiya Takaki¹, Koji Nishida¹, Akio Tomiyama² (1. Institute of Nuclear safety System, Inc., 2. Kobe University)

Keywords:Vertical pipe, Countercurrent flow, Flooding, Interfacial friction factor

Flooding occurs at the square top end of the vertical pipe in a pressurizer surge line under countercurrent flow conditions. In this study, we evaluated interfacial friction factors f_i in vertical pipes under flooding at the square top end from the pressure gradient data in air-water experiments with the diameter of D = 20 and 50.8 mm and in steam-water experiments with D = 20 mm and the pressure of P = 0.6-4.1 MPa, and derived a correlation for f_i as a function of the gas Wallis parameter and dimensionless diameter.