A momentum explanation for the unsatisfactory Betz model prediction in highly loaded wind turbines
A momentum explanation for the unsatisfactory Betz model prediction in highly loaded wind turbines
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高负载风力涡轮机中 Betz 模型预测不理想的动量解释
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
N. Theodoropoulos
中科院分区：
文献类型：
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作者：
D. Georgiou;N. Theodoropoulos
本研究试图为著名的贝茨模型的预测与高负载风力涡轮机性能的实际结果之间的严重偏差提供直接解释。新模型通过重新制定相关的一维流动方程来解释内部和外部流的相互作用（动量和能量传递）。这可以很好地预测“风车螺旋桨”测试中实验测量的 CT = f(a) 关系。结果表明，尽管最大功率系数接近 Betz 预测的值，但对于超出“最佳”点的转子负载，该系数会急剧下降（而不是保持稳定，接近 CP = 0.5 值）。进一步的分析表明，这种“效率”下降的主要原因是通过涡轮转子的质量通量减少，这显然是因为尾流涡流阻塞了其在内部的通道。版权所有 © 2010 约翰威利父子有限公司
The present study attempts to provide a direct explanation for the strong deviation between the predictions of the well-known Betz model and the actual results for the performance of highly loaded wind turbines. The new model accounts for the inner and outer stream interaction (momentum and energy transfers) by reformulating the relevant one-dimensional flow equations. This results in a very good prediction of the experimentally measured CT = f(a) relationship in ‘windmilling propeller’ tests. It is shown that although the maximum power coefficient is near that predicted by Betz, for rotor loadings beyond the ‘optimum’ point, this drops sharply (instead of remaining steady, near the CP = 0.5 value). Further analysis shows that the main contributor for this ‘efficiency’ degradation is the reduction in the mass flux through the turbine rotor, apparently because of the wake vortices that block its passage in the inner section. Copyright © 2010 John Wiley & Sons, Ltd.