Two-Phase Gas-Liquid Flow in Pipes with Different Orientations


Book Description

This book provides design engineers using gas-liquid two-phase flow in different industrial applications the necessary fundamental understanding of the two-phase flow variables. Two-phase flow literature reports a plethora of correlations for determination of flow patterns, void fraction, two- phase pressure drop and non-boiling heat transfer correlations. However, the validity of a majority of these correlations is restricted over a narrow range of two -phase flow conditions. Consequently, it is quite a challenging task for the end user to select an appropriate correlation/model for the type of two-phase flow under consideration. Selection of a correct correlation also requires some fundamental understanding of the two-phase flow physics and the underlying principles/assumptions/limitations associated with these correlations. Thus, it is of significant interest for a design engineer to have knowledge of the flow patterns and their transitions and their influence on two-phase flow variables. To address some of these issues and facilitate selection of appropriate two-phase flow models, this volume presents a succinct review of the flow patterns, void fraction, pressure drop and non-boiling heat transfer phenomenon and recommend some of the well scrutinized modeling techniques.










Study of Flow Patterns and Void Fraction in Inclined Two Phase Flow


Book Description

In the field of multiphase flow, much research has been done on flow patterns and void fraction in vertical upward, vertical downward and horizontal pipes with only very little investigation done in inclined pipes. Experimental investigation was conducted in present study over six pipe orientations (+5°, +10°, +20°, -5°, -10° & -20°) using air-water as fluid combination in a 12.7 mm diameter pipe. Flow visualization was conducted for flow pattern identification, flow pattern maps were developed showing effect of pipe orientation on flow pattern transition boundaries and 700 void fraction data points were measured and analyzed. Effect of pipe orientation on void fraction was also observed and reported. Fourteen void fraction correlations were selected for experimental data prediction based on previous works and the best performing void fraction correlation for upward inclined pipe, downward inclined pipe and near horizontal pipe orientation was determined. A unique phenomenon called flow reversal in co-current two phase flow was observed in upward inclined pipe orientation and investigated in present study. Flow reversal was investigated using Bernoulli's equation and dimensionless numbers (Froude, Reynolds & Weber number) which gave in-depth analysis of this phenomenon.




An Experimental Investigation of Two-phase, Two-component Flow in a Horizontal, Converging-diverging Nozzle


Book Description

A discussion is presented of an investigation of the flow characteristics in a horizontal, converging-diverging nozzle for a two-phase, air- water system. The primary consideration, to determine the effects of accelerating the liquid phase by the gaseous phase, was measured in terms of nozzle exit water velocity, exit slip ratio, and exit acceleration factor. A gamma-ray-attenuation technique was used to determine these values by determining the average cross-sectional void fraction, the ratio of gas volume to total volume, for the air-water mixture.