Experimental study on void fraction of two-phase flow inside a micro-fin tube

Abstract

In this paper the void fraction and flow pattern of the two-phase flow in a micro-fin tube were investigated experimentally for a pure refrigerant HFC134a. The experiment was carried out at a pressure range of 0.6 and 1.2MPa with mass velocities of 90 and 180kg/m^2 s, in which the vapor quality varied from 0 to 1. The void fraction was measured by means of simultaneously closing valves of both sides of the test tube at adiabatic condition. Experimental results for the micro-fin tube were compared with previous correlations for smooth tube. It was found that experimental data of the micro-fin tube were lower than predicted results using correlations for smooth tube. As a trial, an empirical correlation was proposed, based on the present experimental results. The observation of the flow pattern through a sight glass was also carried out with a camera. The observation results were compared with modified Baker's map.