Studies of Liquid Film Flow in Two-Phase Annular and Annular-Mist Flow Regions : (Part 2, Upflow in a Vertical Tube)

Abstract

Experimental data are presented on the pressure drop, mean liquid film thickness, state of gas-liquid interface and droplet entrainment for upward annular-mist two phase flow in a vertical tube. Using these data, the relations between the shear stress at gas-liquid interface, the liquid film flow rate and the mean film thickness are investigated, and the characteristics of the mean film thickness with respect to the film Reynolds number are revealed by comparing with the analytical predictions for laminar and turbulent films. A heat transfer experiment is also performed and the results are compared with the analytical values of heat transfer coefficient for laminar and turbulent film flow. On the basis of the experimental data of heat transfer coefficient, the nondimensional thickness of the laminar sublayer of liquid film is calculated for both upflow and downflow, and correlated with the nondimensional film thickness. The result represents the difference in flow state between the upflow film and the downflow film.