Diffuser Performance for Draft Tube Applications

Available information on diffuser performance is summarized in relation to draft tube applications. This paper is particularly directed at the implications of basic research with these effects on the optimum design of draft tubes. The limited (published) systematic experiments with model hydraulic turbines are extremely valuable in interpreting the basic diffuser data. The experimentally-determined dimensions for many actual applications serve as a guide, but detailed flow data are usually missing. Finally, the possibilities for numerical analyses and the need for further research are discussed.