Design of Low-Cost Axial-Flow Hydraulic Turbines for Very Low Head Micro Hydro Power Plants

Nearly one million people in Amazon still don't have reliable access to electricity. Moreover, the rural electricity grid is mostly single-phase, ground-return type, with poor energy quality and high expenses. This study examines very low head micro hydro power (MHP) installations in Amazon, emphasizing the integration of multiple axial-flow turbines. It includes an analysis of flow duration curves and key curves, both upstream and downstream, to design an MHP with two or more units aimed at maximizing annual energy generation. The presence of multiple turbines is crucial due to the substantial annual flow variation in the Amazon rivers. This research supports the design of small, cost-effective axial-flow hydraulic turbines. The design applies the minimum pressure coefficient criterion to increase turbine efficiency. Computational Fluid Dynamics (CFD) simulations forecast turbine efficiency and flow behavior. The CFD model is validated against an existing experimental study from the literature on a propeller turbine with a curved plate blade, which is similarly used in this study due to cost reasons. The study also explores the implications of including inlet guide vanes (IGV). A case study is showcased for a location at a small bridge in Vila do Janari, situated in the southeastern part of Pará state, where heads range from 1.4 to 2.4 m and turbine flow rates span from 0.23 to 0.92 m³/s. The optimal configuration shows the potential to generate 63 MWh/year.