Performance investigation of a kaplan hydraulic turbine draft tube using CFD techniques

Abstract

The draft tube has an important role in the overall efficiency of water turbines. The enhancement of draft tube performance has been under considerable attentions during the past decade. As the flow field characteristics inside the draft tube can reveals the possible trends for enhancing its performance therefore the computational fluid dynamics techniques have been used extensively in this regard. A full 3 – D steady turbulent flow numerical simulation has been conducted for a prototype hydraulic Kaplan turbine. The effect of some key parameters such as guide vane opening and runner blade angles on the draft tube performance are studied. The results are presented as the variation of draft tube pressure recovery factor in terms of these parameters. Some features of draft tube flow field are also reported.