フランシス水車の走放し速度について

概要

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There has not been presented the method of calculation of run away speed of Francis water turbine. The author showed that the run away speed ratio R_n is represented by the equation R_n=ζq_<R0>, from the equation of loss work at the condition of R_n, where, q_<R0> is the ratio of water quantity at the speed of run away to that at the normal speed. q_<R0> is calculated by the equation of energy balance at the condition of run away speed. If the efficiency of the Francis water tusbine is known, ζ is calculable, and finally R_n can be computed. Author also presents a simple formula of run away speed at the maximum effidiency. By this formula, that is obivious that the most effective terms to run away speed of Francis water turbines are the peripheral speed of runner at the normal speed and the ratio of the exit mean diameter to inlet the diameter of runner.
一般社団法人日本機械学会の論文