Numerical Study of the Opening Angle Incidence in Michell-Banki Turbine’s Performance without Guide Blades

Abstract

Technologies that take advantage of alternative sources, such as Michell-Banki turbines, can improve electric power conditions in rural or non-interconnected areas with low environmental impact, but they need to be further studied to better understand their phenomenology and ways to increase their performance. The numerical evaluation of rotors under specific operating conditions results in efficiency curves for the evaluated prototypes such that devices that take full advantage of the flow conditions of a given location are proposed. Considering the above, the main objective of this work was to design the rotor and the injector of a Michell-Banki turbine and to evaluate it numerically for the conditions of 0.24 m3/s and 18 m of head available at a point with potential energy use in the irrigation district Canal Iguá in Huila - Colombia. The design was made following OLADE recommendations, and the simulations were made utilizing computational fluid dynamics, the k- ω turbulence model was used and the torque was monitored, then the GCI and TCI were calculated to establish the numerical uncertainty of the results. Finally, the numerical curves of efficiency versus rotor speed were created. Both the design and simulation results show that the design is feasible for the operating conditions and meets the expectations of serving for the installation of a 20 kW micro-hydroelectric power plant at the site, but the design predicted an atypically high 86.3% efficiency, while the simulation reported an atypically low 51.8%, being 78% the average reported according to OLADE.