Performance Improvement of a Drag Hydrokinetic Turbine

Mabrouk Mosbahi,Bouzid Mosbahi,Zied Driss,Mariem Lajnef,Mouna Derbel,Costanza Aricò,Marco Sinagra

doi:10.3390/w13030273

Mabrouk Mosbahi, Bouzid Mosbahi + Show 5 more

Open Access

https://doi.org/10.3390/w13030273

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Abstract

Hydropower is at present in many locations, among all the other possible renewable energy sources, the best one for net cost per unit power. In contrast to traditional installation, based on water storage in artificial basins, free flow river turbines also provide a very low environmental impact due to their negligible effect on solid transport. Among them, kinetic turbines with vertical axis are very inexpensive and have almost zero impact on fish and local fauna. In application to tidal waves and sea waves, where vertically averaged velocities have alternate direction, a Savonius rotor also has the advantage of being productive during the whole time cycle. In this work, the effect of an upstream deflector system mounted upstream of a twisted Savonius rotor inside a channel has been investigated through numerical simulations and experimental tests. Numerical simulations were carried on using the ANSYS FLUENT 17.0 software. Based on this numerical study, it is shown that the proposed deflector system has improved the power coefficient of the Savonius rotor by 14%. The utilization of this new design system is predicted to contribute towards a more efficient use of flows in rivers and channels for electricity production in rural areas.

Highlights

The harvesting of hydrokinetic energy from river streams and small irrigation channels has recently become an important source of renewable energy [1], even in the case of low speed water flow [2,3,4]
The twisted Savonius water turbine is ranked as a drag-type of vertical axis water turbine, which can rotate at low speed water flow, starting from any position of the blades
The Savonius rotor is tested in an irrigation canal with an inlet velocity of 0.86 m·s−1

Summary

Introduction

The harvesting of hydrokinetic energy from river streams and small irrigation channels has recently become an important source of renewable energy [1], even in the case of low speed water flow [2,3,4]. The twisted Savonius water turbine is ranked as a drag-type of vertical axis water turbine, which can rotate at low speed water flow, starting from any position of the blades. The difference between the drag force applied on the concave and on the convex side of its blades results in a net torque, which remains almost constant during rotation if a twisted shape is adopted in the axis direction instead of a cylindrical one. Its simple structure makes it easy to be installed in an irrigation channel or even in a river.

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