Cfd Approach for Prediction of Efficiency of Francis Turbine

Turbine is the most critical component in hydropower plants because it affects the cost as well as overall performance of the plant. Hence, for the cost effective design of any hydropower project, it is very important to predict the hydraulic behavior and efficiency of hydro turbines before they are put in actual use. Experimental approach of predicting the performance of hydro turbine is costly and time consuming compared to CFD approach. The aim of the paper is to predict the performance and efficiency of Francis turbine using CFD approach and to validate the same with model testing results. The overall efficiency of the turbine is determined based on the fundamental equation i.e. ratio of output to input power. The various parameters used in the equation depend on the type of boundary conditions used for the numerical simulation. Two sets of boundary conditions viz. (i) pressure inlet and pressure outlet and (ii) mass flow inlet and pressure outlet were used. The overall efficiency predicted with CFD approach was compared with the model testing results obtained from the manufacturer and very good agreement was found. CFD approach may be helpful in improvement of the existing efficiency measuring techniques and evaluation of the performance of hydro turbines.