engleski

CFD prediction of high head Francis turbine performance

Flow in the high head Francis turbine, installed in the HPP Dubrovnik, is simulated in the paper. The geometry of the turbine components, including the spiral casing, stay vanes, guide vanes, runner and draft tube, is modelled with CAD software using 2D drawings. ANSYS Fluent Software is used for the numerical simulations of the entire turbine flow with the frozen rotor and sliding mesh interface between the stationary and rotating domain. The realizable k-ε turbulence model with scalable wall functions is applied. While simulating the turbine flow a wicket gate opening was varied for given turbine discharges in order to get net head close to the operating conditions. The computational fluid dynamics (CFD) predicted performance of the full-scale turbine is compared with the experimental data from the model tests and the operating data of installed turbine. The CFD results for the turbine power and efficiency fall close to the experimental ones at design flow and off-design conditions as well. The potential increase in draft tube efficiency is analyzed via CFD for the several arrangements of piers inside the existing draft tube at different turbine loads

CFD, Francis turbine

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