Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior

Experiments are reported on an air–water mixture flowing through an orifice in a vertical pipe. Time series of cross-sectionally averaged void fractions have been measured at nine axial positions by using a conductance probe technique. A series of six orifices with different thicknesses and aperture...

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Main Authors: Zeghloul, Ammar, Azzi, Abdelwahid, Saidj, Faiza, Azzopardi, Barry J., Hewakandamby, Buddhika N.
Format: Article
Published: 2015
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Online Access:https://eprints.nottingham.ac.uk/35549/
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author Zeghloul, Ammar
Azzi, Abdelwahid
Saidj, Faiza
Azzopardi, Barry J.
Hewakandamby, Buddhika N.
author_facet Zeghloul, Ammar
Azzi, Abdelwahid
Saidj, Faiza
Azzopardi, Barry J.
Hewakandamby, Buddhika N.
author_sort Zeghloul, Ammar
building Nottingham Research Data Repository
collection Online Access
description Experiments are reported on an air–water mixture flowing through an orifice in a vertical pipe. Time series of cross-sectionally averaged void fractions have been measured at nine axial positions by using a conductance probe technique. A series of six orifices with different thicknesses and apertures were employed. The Probability Density Function, the Power Spectral Density of the time series of cross sectionally averaged void fractions and the cross-correlation of time series from adjacent probes have been obtained to determine the effect of the orifice on the flow characteristics. The diameter area ratio and the thickness of the orifice have a higher influence on bubbly than on slug and churn flows. The recovery length is about 20, 10 and 7 pipe diameter downstream the orifice for these three flow patterns respectively. Homogenization effect needs a minimum liquid superficial velocity. Its position occurs depends on the value of this velocity and on the orifice fractional open area. Just downstream the orifice, the structure velocity increases for the bubbly and slug flows and decreases for churn flow. For bubble and slug flows, there is persistency of the frequency when passing through the orifice from the upstream to the downstream pipe.
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spelling nottingham-355492020-05-04T17:17:51Z https://eprints.nottingham.ac.uk/35549/ Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior Zeghloul, Ammar Azzi, Abdelwahid Saidj, Faiza Azzopardi, Barry J. Hewakandamby, Buddhika N. Experiments are reported on an air–water mixture flowing through an orifice in a vertical pipe. Time series of cross-sectionally averaged void fractions have been measured at nine axial positions by using a conductance probe technique. A series of six orifices with different thicknesses and apertures were employed. The Probability Density Function, the Power Spectral Density of the time series of cross sectionally averaged void fractions and the cross-correlation of time series from adjacent probes have been obtained to determine the effect of the orifice on the flow characteristics. The diameter area ratio and the thickness of the orifice have a higher influence on bubbly than on slug and churn flows. The recovery length is about 20, 10 and 7 pipe diameter downstream the orifice for these three flow patterns respectively. Homogenization effect needs a minimum liquid superficial velocity. Its position occurs depends on the value of this velocity and on the orifice fractional open area. Just downstream the orifice, the structure velocity increases for the bubbly and slug flows and decreases for churn flow. For bubble and slug flows, there is persistency of the frequency when passing through the orifice from the upstream to the downstream pipe. 2015-09-03 Article PeerReviewed Zeghloul, Ammar, Azzi, Abdelwahid, Saidj, Faiza, Azzopardi, Barry J. and Hewakandamby, Buddhika N. (2015) Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior. International Journal of Multiphase Flow, 74 . pp. 96-105. ISSN 0301-9322 Orifice; Two-phase; Upward; Void fraction; Conductance; Frequency http://www.sciencedirect.com/science/article/pii/S0301932215001056 doi:10.1016/j.ijmultiphaseflow.2015.04.013 doi:10.1016/j.ijmultiphaseflow.2015.04.013
spellingShingle Orifice; Two-phase; Upward; Void fraction; Conductance; Frequency
Zeghloul, Ammar
Azzi, Abdelwahid
Saidj, Faiza
Azzopardi, Barry J.
Hewakandamby, Buddhika N.
Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior
title Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior
title_full Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior
title_fullStr Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior
title_full_unstemmed Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior
title_short Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior
title_sort interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior
topic Orifice; Two-phase; Upward; Void fraction; Conductance; Frequency
url https://eprints.nottingham.ac.uk/35549/
https://eprints.nottingham.ac.uk/35549/
https://eprints.nottingham.ac.uk/35549/