Browsing by Author "Elliott, Alexander"

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    Gas-liquid flow regime maps for horizontal pipelines: predicting flow regimes using dimensionless parameter groups
    (Begell House, 2022-10-27) Osundare, Olusegun Samson; Elliott, Alexander; Falcone, Gioia; Lao, Liyun
    Flow regime maps are essential to gas-liquid flow applications in many industrial processes to accurately identify the flow regimes before estimating multiphase features. Flow regime classifications were originally based on visual observations of two-phase flow experiments. The observations were mapped on two-dimensional plots (called “flow regime maps”) and the boundaries between regimes determined. Over the years, different coordinates have been proposed for the maps (e.g., superficial velocities and momentum fluxes), in search for parameters that are independent of the given experimental set-up. This paper reports a study on developing new flow regime maps with a broader range of applications by using dimensionless parameter groups as the map coordinates. Various flow regime maps were developed with the use of different combinations of these parameter groups, then they were examined and assessed using datasets from published experimental research and the MultiFlowMet II project for validation. This initial feasibility study develops proof-of-concept flow regime maps that demonstrate the potential of dimensionless parameter groups to more accurately characterise multiphase flow in horizontal pipes, with the optimisation of these maps being considered in future works. The analysis revealed that combinations of the mixture Froude number (Frm) versus the ratio of gas superficial velocity to liquid superficial velocity (vSG/vSL), with the liquid phase Froude number (FrL) versus the gas phase Froude number (FrG) show potential for unambiguous identification and mapping of flow regimes, even for datasets with a wider range of operating conditions.
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    Liquid-liquid flow pattern prediction using relevant dimensionless parameter groups
    (MDPI, 2020-08-24) Osundare, Olusegun Samson; Falcone, Gioia; Lao, Liyun; Elliott, Alexander
    Accurate predictions of flow patterns in liquid-liquid flow are critical to the successful design and operation of industrial and geo-energy systems where two liquids are jointly transported. Unfortunately, there is no unified flow pattern map, because all published maps are based on limited ranges of dimensional parameters. Dimensional analysis was performed on oil-water horizontal flows, to obtain some relevant dimensionless parameter groups (DPG) for constructing flow pattern maps (FPM). The following combinations of DPG were used: (i) the ratio of mixture Reynolds number to Eötvös number versus water fraction, (ii) the ratio of Weber number to Eötvös number versus water fraction, (iii) the mixture Froude number versus water fraction, (iv) the water Froude number versus oil Froude number, (v) the ratio of gravity force to viscous force versus water fraction. From twelve published experimental studies, 2696 data points were gathered and analysed covering a variety of flow patterns including stratified, stratified mixed, dispersed oil in water, dispersed water in oil, annular and slug flows. Based on the performed analysis, it was found that flow patterns could occupy more than one isolated region on the DPG-based flow pattern map. None of the combinations of DPG can mark out all the considered flow patterns, however, some combinations of DPG are particularly suitable for marking out the regions associated with some flow patterns