Experimental Study on Output Characteristics of an Opened Circumferential Flow Type Undershot Water Turbine

In order to recovering the small hydraulic energy that of enough flow rate but the low potential head, the output characteristics of an opened circumferential flow type undershot water turbine was evaluated by the model test and the numerical simulation. In this experiment, the output performance of the water turbine which is the number of blades 8 and the pitch angle -30°was the highest. When the rear inclined impeller rotated one pitch after touching to the water surface, the circumferential momentum and the wetting length of the impeller became larger than the forward inclined impeller. In the case of the undershot water turbine, we scoped that it is effective to design the number of blades appropriately small number in order to not impede the conversion of the momentum to the rotational motion for the blade in the water