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首页> 外文期刊>International Journal on Hydropower & Dams >Hydraulic stability in high-load operation: a new model and its use in Francis turbine refurbishment
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Hydraulic stability in high-load operation: a new model and its use in Francis turbine refurbishment

机译:高负荷运行中的液压稳定性:一种新模型及其在弗朗西斯水轮机翻新中的应用

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摘要

For better flexibility of operation, hydro units should be able to operate reliably in a wide range of loads. Francis turbines are known to be prone to 'rough running' if they are operated far from best-efficiency load. This is basically because, in a Francis runner, blades are not adjustable. As a result, there is just one value of discharge with straight, nearly swirl-free outflow from the runner. This happens in a condition close to best efficiency. At lower or higher flow, the flow enters the turbine draft tube with either positive or negative swirl, and too much swirl may produce various types of flow disturbances. Nevertheless, Francis turbines and pump-turbines can operate acceptably smooth in an ample range of part-load and overload conditions if properly designed. Key to better dynamic performance is the optimal layout and design of the Francis runner. Rehabilitation projects hold additional challenges because of the sub-optimal proportions of older machines. Adapting to match existing unfavourable draft tube shapes can sometimes require great care and experience.
机译:为了获得更好的操作灵活性,水电单元应该能够在各种负载下可靠地运行。众所周知,如果弗朗西斯(Francis)涡轮机在远离最佳效率负荷的地方运行,则很容易出现“粗糙运行”的情况。这主要是因为在弗朗西斯赛跑者中,叶片是不可调节的。结果,只有一个数值,即从转轮流出的流量是笔直的,几乎没有涡流的。这发生在接近最佳效率的情况下。在较低或较高的流量下,气流以正旋流或负旋流进入涡轮导流管,过多的旋流可能会产生各种类型的流动扰动。尽管如此,如果设计合理,弗朗西斯水轮机和水泵水轮机在足够的部分负荷和过载条件下仍可正常运行。更好的动态性能的关键是弗朗西斯赛跑者的最佳布局和设计。由于旧机器的比例不够理想,修复项目面临其他挑战。适应匹配现有不利的引流管形状有时可能需要非常谨慎和经验。

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  • 来源
    《International Journal on Hydropower & Dams》 |2011年第4期|p.84-88|共5页
  • 作者

    P.K. Dbrfler; 0. Braun; M. Sick;

  • 作者单位

    Andritz Hydro AG, Hardstrasse 319, CH-8005 Ziirich, Switzerland;

    Andritz Hydro AG, Hardstrasse 319, CH-8005 Ziirich, Switzerland;

    Andritz Hydro AG, Hardstrasse 319, CH-8005 Ziirich, Switzerland;

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