Broad spectrum quality assessment of flow simulations in Pelton turbine runners

Abstract The presented work lists quantities of interest that are expected from Computer Fluid Dynamics (CFD) simulations over the course of a Pelton runner design. It covers a broad spectrum of heterogeneous quantities, from simple scalar values such as hydraulic efficiency of the runner to time-dependent multi-dimensional data such as the evolution of the water distribution at the outlet of the runner over a jet passing cycle. A method is proposed to perform comparison between simulation results and a set of reference experimental results. The approaches selected to quantify agreement between experimental data and simulation results are explained. Finally, the result of the presented work offers a tool evaluating key performance indicators to quantify the discrepancy between simulation results and actual physical behaviour of the turbine. It aims at helping users of numerical simulations to select the most appropriate simulation configuration either for a given application addressing a limited amount of quantities of interest or when they are interested in the best compromise to predict several characteristics of the flow in a Pelton turbine.