Performance study of spiral Darrieus water rotor with V-shaped blades

Because of the excessive consumption of fossil fuels, the world has begun suffering from the depleting of those sources and wide environmental problems. Hydraulic energy, considered as unlimited and non-detrimental, has become the best refuge to supply world demand while protecting the planet. Above all vertical axis water turbine, for their low cost and independency on water direction, Darrieus turbine takes the advantage to be more suitable for some implementation. Thus, various studies have been carried out to improve its efficiency. This study emphasizes on the effect of the blade chord ratio on a spiral Darrieus water rotor performance which has not been two much explored. An experimental static and dynamic tests realized in an irrigation canal were performed with a 3D printed spiral Darrieus rotor. With the intention of the performances betterment, four spiral Darrieus rotors having a chord ratio equal to 0.25, 0.5, 0.75, and 1, respectively, were tested through numerical simulations using the ANSYS FLUENT 17.0 software. Based on the numerical study, it is provided that the rotor with chord ratio of 0.5 was the optimum. In fact, it gives maximum power coefficient of 0.188 at a tip speed ratio equal to 0.71. The obtained findings present an interesting data that could provide the hydrodynamic characteristics of the water flow for the engineers and designers to improve the performance of the spiral Darrieus rotor.