Prediction of Liquid Film Thickness and Pressure Gradient of Swirling Annular Flows in Vertical Pipes Based on One-Dimensional Three-Fluid Model

Correlations of the interfacial and wall friction factors, fi and fw, and the volumetric flux of droplets, JE, were developed based on the experimental data obtained in our previous studies on swirling annular flows in vertical pipes. The developed correlations of fi and fw in swirling flows consist of fi and fw in non-swirling flows, respectively, with effects of swirl motion. The developed correlation of JE accurately evaluates the characteristics of JE in swirling annular flows, i.e., it decreases with increasing the gas volumetric flux. Calculations based on a one-dimensional three-fluid model were also carried out to examine the validity of the developed correlations. The calculations reproduced well the liquid film thickness and the pressure gradient of swirling annular flows in vertical pipes and a small-scale model of a steam separator.