Gas-Liquid Distribution in the Developing Region of Horizontal Intermittent Flows

Abstract

Experiments have been carried out to analyze the evolution of the air/water flow structure along a horizontal 60 mm i.d. straight pipe. Plug and slug flow regimes were observed. In order to investigate the local structure of the flow, dynamic void fraction measurements have been performed by means of ring impedance probes. From dynamic void fraction measurements the mean void fraction values, the probability distributions of void, the liquid film height in the gas cavities and the slug frequencies have been evaluated. The analysis of the results showed that the flow structure deeply modifies along the pipe and that minor effects have to be ascribed to gas injection mode. The examination of the probability distribution function enabled the identification of the operating conditions at which the transition occurs, thus making it possible to propose a new objective criterion of identification.