フランシス水車羽根車流路の表面あらさの水車性能におよぼす影響

概要

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The effects of runner surface roughness on the performance of a Francis turbine have been studied experimentally. The performance data were obtained for seven various type roughnesses k from 0.007 to 1.0 mm. Preliminarily, the frictional resistance of enclosed rotating disks with the respective roughness was measured for laminar and turbulent flows, in order to relate these different roughnesses to hydraulic frictional resistance. By these disk-friction tests, roughnesses of these surfaces could be expressed by the equivalent Nikuradse sand-grain diameter (equivalent sand roughness). The following conclusions may be drawn from this experimental study. (1) The turbine efficiency diseases in proportion to the frictional resistance of its equivalent sand roughness. (2) With increasing roughness, the maximum efficiency point shifts to the lower steed and the lower flow rate. (3) Concerning the admissible roughness, Schlichiting formula is in good agreement with this experiment.
一般社団法人日本機械学会の論文
1963-08-25