Experimental Investigation of Air-water Two Phase Upflow across Horizontal Tube Bundles : Part 1, Flow Pattern and Void Fraction

Abstract

The present paper deals with experiments of air-water mixtures flow pattern and their mean void fraction in horizontal tube bundles. The tube bundles are staggered with equilateral triangular arrangement of three different pitch/tube diameter ratios (1.4, 1.28, 1.08) and they consist of six different tube rows (7, 9, 11, 13, 15, 20) for each ratio. Experimental ranges are as follows ; Superficial air velocity (cm/s) 1.5 - 50 Superficial water velocity (cm/s) 0.032 - 0.32 Flow direction upward flow The observed mixture flows can be classified into 1. bubbly flow 2. slug flow 3. froth flow 4. spray flow with liquid forming a film around the tubes and spraying from tube to tube downstream. Besides, a simple empirical equation for void fraction is proposed.