论“加权因子”的权重分布对转轮水力开发的导向作用

Guiding Effects of the Weighted Efficiency Factors Distribution on the Hydraulic Turbine Model Runner Development

“加权因子”表是转轮能量指标的计算规则,但表中的权重分布对转轮的水力开发起着导向作用。本文提出的“类抛物线型”权重分布法,按转轮的效率特性η(N)给出权重值,其效率峰值工况点N[η(max)]曲线特征按效率峰值移动规律随水头变化而有规则移动,相关工况点权重所占比例作出相应调整(为简化,本文将电站全水头分为三段分别给出比例规则)。额定水头的效率峰值对应的工况点N[η(max)]具有可选定性,是效率峰值移动的基准点,它反映了转轮具有较高能量指标和较好的稳定性的共同要求。按“类抛物线型”给出权重分布,对开发出综合性能优良的转轮作出了正确的导向。

The table of the weighted efficiency factors in hydraulic turbine bidding documents can not only be used to calculate the energy production of the runner, but also play an important role for guiding model runner development. The method for weighted efficiency factors distribution, type of parabola similarity presented in this paper, weighted efficiency factors are derived by the runner efficiency characteristic curves η（N）. As the efficiency characteristic curve for different head is different by its peak efficiency operating condition N[η（max）], so the proportion of weighted efficiency factors for different heads should be adjusted along the heads. （for a simplify, the whole operating heads for station will be divided into three sections, different roles for weighted factors are given respectively for each head section.）. The rated head efficiency peak operation point N[η（max）]is taken as the reference point for peak efficiency movement, it reflects the high energy performance and a good stability of a runner, the point is selectable. Basing on the type of parabola similarity, the derived weighted factors distribution will correctly guide to develop a excellent model runner with fine general performance.