Multi-fluid model predictions of gas-liquid two-phase flows in vertical tubes

Abstract

A consistent one-dimensional multi-fluid model is developed for the prediction of two-phase flows in vertical pipes. The model is based on the mass, momentum and energy balance equations for every fluid stream involved in the observed two-phase flow pattern, and corresponding closure laws for interface transfer processes. The steady-state balance equations are transformed in a form suitable for a direct application of the numerical integration method for the system of ordinary differential equations. Thermal-hydraulic processes along the whole length of the boiling channel are simulated, from the flow and heating of sub cooled liquid at the flow channel inlet, and up to the liquid film dry out and gas entrained droplets mist flow at the outlet. Also, the model is tested against several partial effects of two-phase flow.