Experimental Study on the Effect of Water Velocity on the Performance of a Cross- Flow Turbine

Abstract

In the field of renewable energy, a growing attention is given to cross flow turbine such as the Darrieus turbine. This turbine, originally used as a wind turbine, is currently used as a water turbine to extract energy from water currents, reservoirs, rivers and oceans to eventually convert into electrical energy.

In the work presented in this paper a series of painstaking experiments, for different velocity of the water flow (V = 0.37 m/s to 0.73 m/s), was conducted (at the Hydro-Pneumatic Power Laboratory of Northeastern University, Boston, USA) to determine the influence of this velocity on the performance parameters of a water Darrieus turbine, such as torque, mechanical power and power coefficient.

The experimental model of the water Darrieus turbine has three NACA0020 blades with a length of 0.216 m, a chord of 0.069 m and a solidity of 2. These blades are fixed at a radius of 0.104 m and an offset angle of 120°.

The main finding from the results analysis, obtained with a good consistency, is the increase of the water flow velocity from 0.37 m/s to 0.73 m/s (corresponding relative Reynolds number from 3.5 10⁴ to 2.8 10⁵) causes an increase in torque, power and power coefficient generated by this turbine model respectively from 0.18 Nm to 0.75 Nm, from 1.66 W to 11.67 W and from 16.92 % to 31.77 %, which gives a 604 % power relative increase for a water velocity relative increase equal to 100 %.