Abstract
The final target of this research is to establish a method for optimizing the design of a draft tube that is installed to recover the static pressure of water flow discharged from a hydraulic turbine runner. For this purpose, detailed measurements of the draft tube internal flows were implemented by using a draft tube element model to make it easy to control the inlet swirl flows, and the measured data was compared with the result of the flow analysis. Since the static internal fl ow in the draft tube was accurately simulated with three-dimensional viscosity analysis using a turbulence model, it proved useful as a designing tool for clarifying flow phenomena. And it becomes clear that the internal flows and the characteristics are largely influenced by the inlet flow velocity distribution, so this fact must be taken into consideration when designing a runner.
