Abstract
The aim of this investigation is to develop an open type cross-flow runner for eco-friendly pico-hydraulic turbine utilizing an extra-low head waterfall. A relative distance between the runner and a waterfall is one of the important factors for a stable generation. It is often necessary to adjust precisely the relative position of the runner every time when flow rate changes. We therefore focused on a flow direction control method with a convex shaped channel. The runner performance was evaluated in two channels which having different curvatures and in various flow rate. As a result, it was found that the control method is applicable for flow direction control. The power coefficient is higher for the channel which has smaller curvature. The method we found is very simple, inexpensive and can also avoid obstructing of water-bone debris at the inlet of channel. It is superior to other control methods from practical point of view for small hydro turbine.
