Numerical analysis for detecting head losses in trifurcations of high head in hydropower plants

Many different types of branching have been developed, such as bifurcation, trifurcation, and manifolds, among others. These configurations are used in penstocks to transport water from surge tanks to power houses in order to feed several turbines at the same time. This arrangement allows for smaller assembly costs in comparison with independent penstock systems. Nevertheless, such installations can generate higher head losses in the system in comparison with single systems. This study focuses on the quantification of these head losses as a function of volumetric flow rate using Computational Fluid Dynamics (CFD) and later validated with previously published results. To determine the coefficient of head losses three mesh settings were analyzed: hexahedral, tetrahedral and hybrid, for both a steady state and transitory flow. Based on the literature, the k-omega) turbulence model was used, with refinement to elements near the wall to check y+. To the simulation transitory, the SAS model was used for analysis of the instability in the trifurcation. (C) 2018 Elsevier Ltd. All rights reserved.