CFD BASED PERFORMANCE ANALYSIS OF REACTION TURBINE

Abstract

India is one of the fastest growing economy in the world. And energy plays a vital role in the development of country’s economy. Day by day the gradual crisis of electricity and pollution from conventional energy sources influence to diversify our source of energy. Hydro power is one of the cleanest form of energy sources in the world. India has a vast amount of small hydro potential, and most of the potentials are located in northern and north-eastern states. As discharge and head determine the capacity of a hydropower plant and plant capacity formulates the design of a hydro-turbine, therefore turbine designing always needs apt attention to produce optimal design. To get better accuracy in designing, it is always needed to study flow analysis data of a turbine model under similar environment as proposed site. As testing the prototype of hydro turbine in laboratory is tedious, time consuming and costly process, it is therefore convenient to perform the whole process under Computational Fluid Dynamics (CFD) environment, which not only reduces experimental cost, but also reduces time consumption. Under present investigation, a CFD based performance analysis of reaction turbines has been carried out. An attempt has been made to compare the simulation results with experimented results in a Francis turbine full-scale model by using RNG κ-ε turbulence model. A comparison study has been done between working turbine setup and CFD model to demonstrate the efficiency variation under different load conditions. The torque produced by the turbine under different discharge conditions has been computed through ANSYS Fluent flow simulation solver. The graphical and tabular representations of efficiency have been included for better understanding of the turbine setup. It has been observed that RNG κ-ε turbulence model has great level of accuracy which predicts maximum achievable efficiency of 94.10% from that Francis turbine setup. The computation process also has represented the velocity contour and pressure contour in the flow circuit with a brilliant GUI representation. Which additionally helps to identify the critically flowing zone and cavitation prone area in the hydraulic circuit. In conclusion, the relevance of CFD based performance study and their limitations has been discussed. The future scope on this relevant field has also been concluded at the end of the study.