The Importance of the Point of Operation of a Kaplan Turbine on Fish Survivability

摘要

Recent investigations on fish survival have shed new light on the importance of the point of operation for a Kaplan turbine. The issue releates to the perception that operating turbines at the point of best efficiency is best for fish survival, and that Kaplan turbines, would have worsening fish passage survival if they were operated at flows less than or more than those having efficiencies less than 1percent below best efficiency. In considering the flow characteristics within the turbines at a range of operating points. the above perception is felt not to be the case. These considerations are based on knowledge of the flow characteristics within the Kaplan turbine obtained from numerical studies using three dimensional viscous flow computations, from evaluation of the flow characteristics within the turbine in a scale model laboratory, and from prototype testing of turbines for fish passage survival. The paper presents results of numerical calculations, scale model turbine observations and field testing for fish survival and draws conclusions with respect to the best condition for fish passage survival based on the physics of the flow field within the turbine, the turbine geometry, and the characteristics of the fish. Recommendations for additional studies to further clarify issues are presented.