To solve the problem that propeller turbines were unfit for working under small discharge conditions in dry seasons, after discussing the influencing factors, a rebuilding scheme for decreasing capacity and increasing efficiency was put forward. The distribution of the axial velocity and the velocity circulation at the inlet and the outlet were researched. Some key technologies in computer aided hydraulic design were solved herein, including unfolded drawing of aero foil converted to cylindrical surface and intelligent extension of curve. An example of a runner blade for a real turbine sets was successfully developed with the self-development CAD software. When the discharge is decreased from 4.5m3/s to 1.5m3/s, the efficiency of the hydraulic turbine increases from less than 30.1% to 82.7%, then the sets can work properly, and its cavitation performances are superior to the original one.

为解决轴流定桨式机组枯水期小流量下不能发电的难题,在分析其原因的基础上提出减容增效实施策略;研究了进出口轴向流速及环量沿半径分布规律;解决了计算机辅助水力设计关键技术难题,包括翼型展开图向计算流面圆柱面转化技术及曲线智能延伸技术;用自行开发的CAD软件为一实际机组设计轴流式叶片,在流量从4.5m3/s减至1.5m3/s时,机组效率从改造前的低于30.1%增大至82.7%,机组能够正常发电,且叶片汽蚀性能优于原转轮汽蚀性能。

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轴流式叶片, 减容增效, 超低比转速, 计算机辅助水力设计

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