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University of Huddersfield Repository Pradhan, Suman Measurement of Bubble Velocity Vectors in Bubbly Air Water Multiphase Flow Original Citation Pradhan, Suman (2010) Measurement of Bubble Velocity Vectors in Bubbly Air Water Multiphase Flow. Doctoral thesis, University of Huddersfield. This version is available at http://eprints.hud.ac.uk/9247/ The University Repository is a digital collection of the research output of the University, available on Open Access. Copyright and Moral Rights for the items on this site are retained by the individual author and/or other copyright owners. Users may access full items free of charge; copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational or not-for-profit purposes without prior permission or charge, provided: • The authors, title and full bibliographic details is credited in any copy; • A hyperlink and/or URL is included for the original metadata page; and • The content is not changed in any way. For more information, including our policy and submission procedure, please contact the Repository Team at: [email protected]. http://eprints.hud.ac.uk/ Measurement of Bubble Velocity Vectors in Bubbly Air Water Multiphase Flow Suman Raj Pradhan August 2010 A thesis submitted to the University of Huddersfield in partial fulfilment of the requirements for the degree of Doctor of Philosophy. The University of Huddersfield Declaration No portion of the work referred to in this thesis has been submitted in support of an application for another degree or qualification of this or any other university or other institute of learning. Suman Pradhan 2 Acknowledgements I would like to express my gratitude to my supervisor, Prof. Gary Lucas, for giving me the opportunity to carry out this research. I would also like to thank him for his support and advice during the research, and for reading all the draft copies of this thesis. I would also like to thank my second supervisor Dr. R. Mishra for his support and guidance. I would like to thank the technicians at the University of Huddersfield for their help in manufacturing, and repairing, the varied equipment that I have needed. I would particularly like to thank Jack Briggs, Dennis Town, Peter Norman, Richard Bailey and David Bray for tolerating me for almost three years and also for their valuable help and support when the technical work had to be carried out. Last not the least I would like to sincerely thank to colleague Dr. X. Zhao for his contribution and expertise that has been put into this research project. Outside work I would like to acknowledge the endless help and support of my family who I know always meant well even if they didn’t show it. Last, but by no means least, I would like to thank Sima Limbu for reading, editing my thesis and her almost endless support and patience throughout the research. I would also like to thank Hannah Treasure, Christine Hunt and John Wilson for giving some of their valuable time to proof read the chapters from my thesis. I would also like to acknowledge the financial assistance of the University Of Huddersfield (grant no. REU 010) Suman Pradhan 3 Abstract Measurement of the volumetric flow rate of each of the flowing components in multiphase flow is often required and this is particularly true in Production Logging applications. Thus, an increasing level of interest has been shown in making flow rate measurements in multiphase flow. A new generation of tomographic instrument, which enables measurement of the instantaneous local velocity vector and the instantaneous local volume fraction of the dispersed phase, is now being introduced. However validation and calibration of such instruments is necessary. This thesis describes the development of a miniaturised local four-sensor conductivity probe capable of acquiring measurements of the local velocity vector, gas volume fraction and the local axial gas velocity in the bubbly gas-liquid flows. Experimental techniques in which the probe was used to obtain the local gas velocity vector and the local gas volume fraction in a bubbly gas-liquid flow are also described. High speed cameras are introduced for the measurement of the reference velocity of the bubbles. The camera images are also used to plot the trajectory of any bubble that hits all four-sensor of the probe. Extensive experimental results showing the distribution of the local gas volume fraction and the local axial, azimuthal and the radial bubble velocity components in vertical and swirling gas-liquid flows are presented. Suman Pradhan 4 Table of Contents Declaration…………………………………………………………………………....2 Acknowledgements…………………………………………………………………...3 Abstract……………………………………………………………………………….4 Table of contents.……………………………………………………….…………....5 List of Figures……………………………………………………………………….14 List of Tables………………………………………………………………….……..26 Nomenclatures………………………………………………………………………28 1. Chapter 1 - Introduction ……………………………………………….…..….37 1.1. Generalities ………………………………………………………………….37 1.2. Types of multiphase flow…………..………….………………………..….. 38 1.3 Application of multiphase flows …………………………………………….42 1.3.1 Multiphase flow in oil and gas industry……………………….……….42 1.3.2 Multiphase flow in the mining industry ………………………………..43 1.3.3 Multiphase flow in nuclear plants……………………………………...44 1.3.4 Multiphase flow in chemical industry………………………….………45 1.4 Research aims and objectives…...…….…………………………………..….47 1.5 The format of the thesis………………………………………………………48 2. Chapter 2 – Literature review………………………………………………...51 2.1 Non-Intrusive methods………………………………………………………51 Suman Pradhan 5 2.2 Intrusive methods. ………………………………………………………......51 2.2.1 Heat transfer probes…………………………………………………....52 2.2.2 Ultrasound probes …………………………………………………......56 2.2.3 Needle probes…………………………………………………..............62 2.2.3.1 Optical probes ………………………………………………….62 2.2.3.2 Conductance needle probes …………………………………….66 2.3 Conductance probe …………………………………………………..............67 2.4. Theory of the dual-sensor conductance probe. ……………………………...73 2.5. Theory of the four-sensor probe……………………………………………..78 2.5.1 A model for determining the bubble velocity vector from seven time delays ………………………………………………………………………...81 2.5.2 Comments on the model………………………..………………………87 2.6 The rotary index dual-sensor probe……………………..…..………………..89 3. Chapter 3 - Manufacturing of probe …………………………..……………. 93 3 Probe fabrication…………………………………...……………...…………...93 3.1 Steps of probe manufacturing…………………………………………..….....93 3.1.1 Fabrication of a new design four-sensor probe (PN1)...…………..…...95 3.1.1.1 Steps of fabrication of a four-sensor probe ……………………..…...98 3.2 Miniature four-sensor probe (PN2)…………………………………………103 3.2.1 Advantage of miniature new probe PN2……………………………...104 3.2.2 Steps for manufacturing probe PN2 ………………….………………108 Suman Pradhan 6 3.3 Measurement of probe………………………………………………………111 3.3.1 Measurement of a probe PN1 ……………….………………..………114 3.3.2 Measurement of the new miniaturised probe PN2 ...…………………116 4. Chapter 4 - Sensitivity analysis ……………………………………………... 120 4.1 Effect on polar angle α and azimuthal angle β due to the error on measured dimensions…………………………………………………………....................120 4.1.1 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in z1,meas ..…………………………………………………………121 4.1.2 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in z ,2 meas …...………………………………..……………………123 4.1.3 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in z ,3 meas .…………………………………………………………125 4.1.4 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in z ,2 meas (increasing) and z ,3 meas (increasing) ……………………127 4.1.5 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in z ,2 meas (increasing) and z ,3 meas (decreasing) …..…………….…129 4.1.6 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in z ,2 meas (decreasing) and z ,3 meas (increasing) ………………..…132 4.1.7 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in z2 (decreasing) and z3 (decreasing) ...…………………………134 Suman Pradhan 7 4.2 Effect on the calculated polar angle α c and azimuthal angle βc due to the errors in the measured time intervals δ tii ,meas (where i = 1, 2 and 3) …..……..136 4.2.1 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in time intervals δ t11 ,meas ………………………...………………136 4.2.2 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in time intervals δ t22 ,meas ………….……………………………...138 4.2.3 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in time intervals δ t33 ,meas ..……………….………………….…...140 4.2.4 Effect on the calculated polar angle α c and azimuthal angle βc due to the error in multiple time intervals δ tii ,meas …………….……………….....143 4.2.4.1 Effect on the calculated polar angle α c and azimuthal angle βc using Condition 1 ...………………….…………………………….....144 4.2.4.2 Effect on the calculated polar angle α c and azimuthal angle βc using Condition 2 ,…………………….……………………………...146 4.2.4.3 Effect on the calculated polar angle α c and azimuthal angle βc using Condition 3 …………………….…………….………………...147 4.2.4.4 Effect on the calculated polar angle α c and azimuthal angle βc using Condition 4 .…………………….……………………………...149 4.3 Conclusion………………………………….…………………………….....150 5. Chapter 5 - Electronic circuits used in measurements …………………..…152