Improvement of Cross Flow Turbine Efficiency in Low Discharge Operation

Abstract

To achieve sustainable society, a hydroturbine with not only the large but also small/mini/micro capacities have been paid attention for power generation. A cross-flow turbine can work effectively at comparatively low head and/or low discharge, and a runner and an inlet nozzle profile have been optimizing. In this paper, the model turbine was prepared in accordance with a traditional design, and the performances and the flow conditions were investigated experimentally at various operating conditions. The hydraulic efficiency is doubtlessly maximum while the guide vane is at the normal/design position and deteriorates in a lower discharge adjusted by the guide vane. Such deteriorations are caused by unacceptable flow conditions in the inlet nozzle. To improve the efficiency dramatically in a lower discharge, the guide vane equipped with a current plate was proposed and the fruitful effect of the plate about the efficiency was confirmed experimentally.