Abstract
There are lots of sites with low head less than 2m such as rivers and wasted water flows. The effective utilization of low head water power as local energy source is becoming more and more vital. However, these extra-low head hydropower have been abandoned due to poor cost-effectiveness of conventional turbines. The Darrieus-type water turbine has been proposed as a suitable one for low head utilization due to its low-cost and simple structure. In the present paper, a ducted Darrieustype water turbine with a staggered blade arrangement is investigated experimentally to improve the torque variation in one revolution of the runner and the stable operation in the case of convergent walled inlet casing, giving high runner efficiency in comparison with a parallel walled inlet casing. Results of staggered and normal blade arrangements are compared in cases of parallel and convergent inlets. The turbine characteristics are made clear and discussed from the standing point of practical use.
