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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-472-4

ISBN Online: 978-1-56700-471-7

3rd Thermal and Fluids Engineering Conference (TFEC)
March, 4–7, 2018, Fort Lauderdale, FL, USA

CFD MODELLING AND VALIDATION OF LOSS COEFFICIENTS FOR PENSTOCK BIFURCATIONS IN HYDROPOWER SCHEMES

Get access (open in a dialog) pages 395-406
DOI: 10.1615/TFEC2018.cmd.021574

摘要

Manifold arrangements in hydropower schemes with penstock bifurcations lead to head losses in the fluid system. It is important to predict these losses and the impact they have on the energy output of the scheme. Loss coefficients are characteristic to the bifurcation as a function of the bifurcation angle, flow rate and cross-sectional area of the pipes. This paper provides detailed quantitative loss coefficient data for sharp-edged asymmetrical bifurcations for 120 scenarios. Computational Fluid Dynamics (CFD) was carried out by using ANSYS Design Modeler, ICEM and CFX software in conjunction to model and simulate the flow of water through the bifurcation. Pipe angles of 30-degree, 45-degree, 60-degree and 90-degree were analysed for various branch area and flow rate ratios for a Reynolds number of 4.5 × 106. Miller [1]; and Fried and Idelchick [2] are comprehensive sources of loss coefficients for bifurcations. Data in the former book were compiled from isolated research programmes. Whereas the latter book predicts the values purely mathematically without accounting for real flow phenomenon. The loss coefficients calculated using CFD were compared with the values provided by these two sources and found to be in reasonable agreement. Although this study uses a high Reynolds number as commonly observed in hydropower systems, the model can be adapted to different scales and types of operations. The results will provide a digital reference for head loss calculations for pipe bifurcations.