Numerical study of similarity in prototype and model pumped turbines
Numerical study of similarity in prototype and model pumped turbines
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DOI：
10.1088/1755-1315/22/3/032049
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发表时间：
2014-03
期刊：
影响因子：
--
通讯作者：
Z. Li;Z. W. Wang;H. Bi
中科院分区：
文献类型：
--
作者：
Z. Li;Z. W. Wang;H. Bi
采用数值模拟方法对原型和模型水泵水轮机进行了相似性研究，并对局部放电情况进行了详细分析。研究发现，在转静干扰区，流动对流加速，流动分离较小，流态和压力脉动相似程度较高，模型涡轮机的相对压力脉动幅值略高于原型涡轮机。对于转轮内流动对流加速并伴有严重分离的工况，由于两种水轮机不同的雷诺数所带来的流动分离和旋涡形成的拓扑结构不同，相似性大大减弱。在尾水管中，流动是扩散减速的，相似性变得削弱，由于不同的涡带形成的雷诺数的影响。结果表明，模型涡轮机的压力脉动幅值和特征频率均大于原型涡轮机。通过无量纲的Navier-Stokes方程，从理论上讨论了不同压力脉动特性的差异。以上结论均是在不考虑压力钢管响应和共振的情况下通过仿真得出的。
Similarity study of prototype and model pumped turbines are performed by numerical simulation and the partial discharge case is analysed in detail. It is found out that in the RSI (rotor-stator interaction) region where the flow is convectively accelerated with minor flow separation, a high level of similarity in flow patterns and pressure fluctuation appear with relative pressure fluctuation amplitude of model turbine slightly higher than that of prototype turbine. As for the condition in the runner where the flow is convectively accelerated with severe separation, similarity fades substantially due to different topology of flow separation and vortex formation brought by distinctive Reynolds numbers of the two turbines. In the draft tube where the flow is diffusively decelerated, similarity becomes debilitated owing to different vortex rope formation impacted by Reynolds number. It is noted that the pressure fluctuation amplitude and characteristic frequency of model turbine are larger than those of prototype turbine. The differences in pressure fluctuation characteristics are discussed theoretically through dimensionless Navier-Stokes equation. The above conclusions are all made based on simulation without regard to the penstock response and resonance.