Transition of Two Phase Flow Patterns : Transition of Bubble Flow to Other Flow Patterns in Air and Water at Atmospheric Pressure and Temperature

Abstract

Progressive change of flow pattern of two phase flow was studied experimentally in the transition region from bubble flow to slug flow or annular flow. In the experiment, three transparent straight circular tubes which had different diameters were employed for the test section. The water flew upward in the test section and the air was issued from a circular nozzle located at the bottom of the test section. The experiment was performed at atmospheric pressure and temperature. The transition from bubble flow to slug flow is classified into three parts for the region of flow state in the result. The first part is a lump of air contacting the nozzle, the second part is a developing region from bubble flow to bubble cap and the third part is a region between the bubble cap and Taylor bubble. The entrance region from the air nozzle to the Taylor bubble is independent of Reynolds number of the water flow, but depends considerably on the ratio of air flow rate to the flow rates of air and water.