Effect of the Flow Rate on Performance Characteristics of an Axial Flow Hydraulic Turbine with a Collection Device

Abstract

We have developed an axial flow hydraulic turbine with a collection device that aimed at high power by collecting and accelerating the flow of shallow open channel such as agricultural waterway and small river. However, the flow rate of the actual open channel flow changes from moment to moment. Therefore, it is necessary to investigate the performance characteristics under various flow rate conditions. In this study, we investigated the influence of the flow rate on the performance characteristics of an axial flow hydraulic turbine with a collection device in a shallow open channel by performance test and numerical analysis considering free surface. As a result, the power coefficient increased as the flow rate through the open channel increased. This is because although the loading coefficient decreases, the increase of the diffuser pressure recovery coefficient increases the inlet velocity ratio, the input power coefficient increases, and additionally the turbine efficiency increases.