Efficiency Calculation Formula of Propeller Type Water Turbines by their Model experimented Efficiency

Abstract

Aiming at the energy of wake circulation, the author deduced a new type efficiency calculation formula of propeller water turbines. Adding to this formula, assuming that in the velocity diagram, the inlet absolute velocities arrow heads always lie on one fixed straight line, and considering from the side of loss independent of Reynolds' number, the author deduced another efficiency calculation formula for propeller water turbines. But, it turned out exactly the same formula with Francis water turbines. By courtesy of The Factory Hitachi, comparing the full scale experimented efficiency of Kaplan turbine of The River Nippashi, experimented as a propeller turbine, with the calculated efficiencies by the above two formulas recognized close agreement with each other. But, up to maximum efficiency, former formula was better than the latter, and as a whole the latter was better than the former.