Experimental Study on Flow Pattern and Void Fraction of Air-Water and 3 % Butanol Two-Phase Flow in 30o Inclined Mini Channel

Abstract

The study on flow pattern and void fraction of air-water and 3 % butanol two-phase flow in 30^o inclined mini channel was performed experimentally. The aim of the research was to find-out the two-phase flow characteristics of gas and low surface tension liquid, especially flow regime and void fraction. A 1.6 mm inner diameter and 130 mm length circular glass pipe was used as test section. The flow images were found by capturing the flow with high speed camera. From the video, it was obtained the flow patterns and flow pattern map. Besides, the flow void fraction which obtained by image processing. The gas and liquid superficial velocities were set in the range of 0.025 - 66.3 m/s, and 0.033 - 4.935 m/s, respectively. Dry air is used as gas working fluid, while as liquid one was the solution of distilled water and 3% Butanol. The addition of Butanol to the liquid phase was intended to change the liquid surface tension. As a result, it was observed five distinctive flow patterns, namely plug, slug-annular, churn, bubbly, and annular. The separated flow was absent. The change of the liquid surface tension affected to the shifting of some transition boundary line in the flow pattern map. Besides, it influenced to the characteristic of void fraction.