Two-phase horizontal intermittent flow in straight pipes is experimentally investigated, by means of a new impedance meter able to collect void fraction data simultaneously at different pipe locations. The investigation is focused on the two-phase behaviour in the downstream region of pipe restrictions. Experiments on air-water horizontal flows in 40 mm inner diameter pipe are performed. The operating conditions cover the typical values for intermittent flow inception. The pipe restrictions are here realised by means of six different orifice plates, as combination of two restriction ratios and three orifice thicknesses. The measurement technique is based on the measurement of the mixture electrical impedance by means of ring electrodes, very close to the pipe throat section. The probe distances from pipe restriction are in the range of 0.7~2.3 pipe diameters. The new instrumentation allows void fraction data every 0.001 seconds to be collected, hence enabling the reconstruction of the time/space profile of the two-phase pattern (film thickness, slug front, slug tail) in presence of a sudden restriction. The measurements demonstrate that the restrictions generally induce a remarkable increase of the void fraction downstream values, which is associated to a reduction of the film thickness values in the stratified regions

Features of Two-Phase Gas/Liquid Flow at a Combining T Junction - Hold Up Profiles Around The Junction And Upstream Travelling Waves

FOSSA, MARCO;
2004-01-01

Abstract

Two-phase horizontal intermittent flow in straight pipes is experimentally investigated, by means of a new impedance meter able to collect void fraction data simultaneously at different pipe locations. The investigation is focused on the two-phase behaviour in the downstream region of pipe restrictions. Experiments on air-water horizontal flows in 40 mm inner diameter pipe are performed. The operating conditions cover the typical values for intermittent flow inception. The pipe restrictions are here realised by means of six different orifice plates, as combination of two restriction ratios and three orifice thicknesses. The measurement technique is based on the measurement of the mixture electrical impedance by means of ring electrodes, very close to the pipe throat section. The probe distances from pipe restriction are in the range of 0.7~2.3 pipe diameters. The new instrumentation allows void fraction data every 0.001 seconds to be collected, hence enabling the reconstruction of the time/space profile of the two-phase pattern (film thickness, slug front, slug tail) in presence of a sudden restriction. The measurements demonstrate that the restrictions generally induce a remarkable increase of the void fraction downstream values, which is associated to a reduction of the film thickness values in the stratified regions
2004
9788846710758
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/230414
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