HORIZONTAL AIR-WATER FLOW CHARACTERISATION WITH A WIRE MESH SENSOR

The paper presents the experimental study performed in a 19.5 mm inner diameter channel to evaluate the development of the phase distribution in a horizontal flow of an air- water mixture. The flow quality ranges from 0.002 to 0.5 and the superficial velocities range from 0.1 to 10 m/s for air and from 0.008 to 1.5 m/s for water. The investigated flow patterns are stratified, slug/plug and annular. The Wire-mesh sensor measures the local instantaneous conductivity of the two-phase mixture, and is used in the present work to characterize the fluid dynamics of the gas–liquid interface in a horizontal pipe flow. A sensor (WMS200), with an inner diameter of 19.5 mm and a measuring matrix of 16×16 points equally distributed over the cross-section, has been adopted for the measurement. The analysis of the signals allows one to evaluate the average and the local void fraction as a function of time and along the wires (chordal values), in order to obtain some information on the flow characteristics for all the flow patterns. The horizontal and vertical profiles of the void fraction are extracted at different position of the wire grid and are used to describe the evolution of the flow and of the interface for different flow pattern conditions. The effects of the superficial velocity of air and water in the chordal void fraction profiles are presented