Drag reduction phenomenon in viscous oil-water dispersed pipe flow: Experimental investigation and phenomenological modeling

Authors

  • I. H. Rodriguez,

    Corresponding author
    1. Dept. of Mechanical Engineering, Engineering School of Sao Carlos, University of Sao Paulo (USP), São Carlos, SP 13566-970, Brazil
    • Dept. of Mechanical Engineering, Engineering School of Sao Carlos, University of Sao Paulo (USP), São Carlos, SP 13566-970, Brazil
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  • H. K. B.Yamaguti,

    1. Dept. of Mechanical Engineering, Engineering School of Sao Carlos, University of Sao Paulo (USP), São Carlos, SP 13566-970, Brazil
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  • M. S. de Castro,

    1. Dept. of Mechanical Engineering, Engineering School of Sao Carlos, University of Sao Paulo (USP), São Carlos, SP 13566-970, Brazil
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  • M. J. Da Silva,

    1. Forschungszentrum Dresden-Rossendorf e. V., Institute of Safety Research, Dresden 01314, Germany
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  • O. M. H. Rodriguez

    1. Dept. of Mechanical Engineering, Engineering School of Sao Carlos, University of Sao Paulo (USP), São Carlos, SP 13566-970, Brazil
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Abstract

An experimental study on drag-reduction phenomenon in dispersed oil-water flow has been performed in a 26-mm-i.d. Twelve meter long horizontal glass pipe. The flow was characterized using a novel wire-mesh sensor based on capacitance measurements and high-speed video recording. New two-phase pressure gradient, volume fraction, and phase distribution data have been used in the analysis. Drag reduction and slip ratio were detected at oil volume fractions between 10 and 45% and high mixture Reynolds numbers, and with water as the dominant phase. Phase-fraction distribution diagrams and cross-sectional imaging of the flow suggested the presence of a higher amount of water near to the pipe wall. Based on that, a phenomenology for explaining drag reduction in dispersed flow in a flow situation where slip ratio is significant is proposed. A simple phenomenological model is developed and the agreement between model predictions and data, including data from the literature, is encouraging. © 2011 American Institute of Chemical Engineers AIChE J, 2012

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