A FRANCIS TURBINE RUNNER BLADE MODIFIED TO MITIGATE PRESSURE PULSATIONS AND NOISE ASSOCIATED WITH HYDRAULIC INSTABILITIES INSIDE THE RUNNER

摘要

The invention relates to a Francis turbine runner blade modified to mitigate pressure pulsations and noise associated with hydraulic instabilities inside the runner, the turbine comprising a spiral casing, a plurality of stay vanes, a plurality of guide vanes, multiple runner blades each having at least one leading edge of the runner and at least one trailing edge, a hub, a shroud, and a draft tube, the runner is characterized by a modified leading edge defined by a parameter f representing a relative stacking angle between the hub section and successive sections progressing from the hub to the shroud in a span-wise direction, wherein ‘f’, varies along the span in a predetermined relationship , wherein the maximum value of ‘f’ is less than 3.5o for specific speed 225 m-kW and higher and wherein the maximum value of ‘f’ at shroud is less greater than 2o, wherein ‘f’ varies along the span in such a way that the maximum value of ‘f’ is located between 60to 75% of the span-wise distance from the hub. { FIGURE 6 }