Evaluation of the Influence of Upstream Flow on the Energy Characteristics of a Giant Kaplan Turbine

Abstract

For the giant Kaplan turbine, the reservoir dam and the retaining dam can affect the internal flow characteristics of the turbine and alter its hydraulic performance. Different heads and flows have different characteristics at the inlet of the turbine. This article conducts a numerical study on the upstream reservoir of a giant Kaplan turbine using the Volume of Fluid (VOF) method and predicts the impact of the upstream reservoir on the unit flow, efficiency, and output. After considering the impact of the upstream reservoir area, due to the uneven distribution of flow in the upstream reservoir area, the efficiency of the three units under the same water level and inflow conditions has a consistent trend with the ideal situation as the unit flow rate of the units changes, and some units have higher efficiency curves than the ideal situation. However, some units are affected by the diversion wall, resulting in streamline deviation, and their efficiency curve is lower than the ideal situation. The output also has a similar situation, especially when the upstream water level is low, the output significantly decreases.

Keywords

• Kaplan turbine
• CFD
• upstream reservoir
• energy characteristics