Investigation on hydraulic characteristics of a model and prototype bulb turbine based on similarity criteria

Abstract From the perspective of the world hydropower utilization trend, the medium and high head hydraulic resources are gradually decreasing, and along with much more attention to the ecological environment and land resource constraints, low-head hydropower plants have been becoming particularly prevalent. Benefit from compact structure, less investment, high capacity and wide operation range, bulb tubular turbines have come up to be the optimal option for the development and exploitation of low-head energy resources and been widely applied. In this paper, based on measurement data and CFD simulation results of model and prototype, scale effect which derived from similarity law was picked up to investigate the hydraulic performance and operating properties. Through comparison and analysis, it’s concluded that distinct from high-head application similarity conversion turns out to be more complicated for bulb turbines in case of flow characteristics, and it’s recommended that this conversion be further modified considering different boundary conditions. Such achievements will be of great help to look into the mechanism of ratio effect and accelerate research progress.