EFFECT OF PIPE DIAMETER AND LIQUID VISCOSITY ON HORIZONTAL STRATIFIED FLOW (TWO-PHASE, WAVE GENERATION)

This thesis is concerned with understanding the stratified two-phase flow in a horizontal pipe. A linear analysis is used to analyze the stability of a stratified flow and a model is developed for predicting pressure drop and film thickness.; Experiments were conducted with gas-liquid flowing in horizonal pipelines with diameters of 2.52 cm and 9.53 cm to determine the interfacial instabilities that exist in stratified flow and to measure the pressure losses and holdup. The liquid viscosity was varied from 1 cp to 80 cp.; Three types of instabilities are defined: Regular two-dimensional waves are associated with pressure variations in phase with the wave slope. Irregular large amplitude waves and atomization are associated with pressure variations in phase with the wave height. The linear instability theory is used to provide a physical interpretation and design equations to predict conditions for the initiation of these instabilities.; A method to predict the film thickness and the pressure losses is proposed. A one-dimensional model for the liquid phase, applicable for laminar of turbulent flows, is developed by applying the concept of eddy viscosity. The gas phase is treated as a plug flow using the Blasius law. Based on extensive data an empirical equation for the interfacial friction factor is suggested. The pressure losses and hold-up are determined, through an iterative procedure, from the prescribed flow conditions, flow properties and pipe size. The model appears to give much better predictions than any model now available.