A free-surface and blockage correction for tidal turbines
A free-surface and blockage correction for tidal turbines
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DOI：
10.1017/s0022112009005916
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发表时间：
2009-04-10
影响因子：
3.7
通讯作者：
Peiro, J.
中科院分区：
文献类型：
--
作者：
Whelan, J. I.;Graham, J. M. R.;Peiro, J.
利用作动器圆盘理论模拟了自由表面接近对潮汐水轮机流场的影响。理论结果提出了潮汐流涡轮机的阻塞配置，如线性阵列，考虑到自由表面和海床的接近。将理论计算结果与利用多孔盘和多孔条模拟明渠流场的实验结果进行了比较。在水槽和风洞中进行的水平轴涡轮机模型性能的更详细测量补充了这些结果。这两组实验分别代表高度阻塞和有效未阻塞的情况。自由表面接近效应的理论模型为轴向感应提供了阻塞校正，可纳入叶片单元动量代码。用这种代码得到的性能预测与低叶尖速比下C(P)和C(T)的实验结果很好地吻合。随着叶尖速比的增加，随着涡轮尾迹进入反向流动状态，这种一致性减弱。根据Maskell的原理对该区域的CT进行了修正，从而提供了更好的一致性。
The effects of free-surface proximity on the flow field around tidal stream turbines are modelled using actuator disc theory. Theoretical results are presented for a blocked configuration of tidal stream turbines such as a linear array that account for the proximity of the free surface and the seabed. The theoretical results are compared to open channel flow experimental results in which the flow field has been simulated using a porous disc and strip. These results are complemented by more detailed measurements of the performance of a model horizontal-axis turbine carried out in a water flume and a wind tunnel. The two sets of experiments represent highly blocked and effectively unblocked cases, respectively. The theoretical model of the effects of free-surface proximity provides a blockage correction for axial induction that can be incorporated in blade element momentum codes. The performance predictions obtained with such a code are in good agreement with the experimental results for C(P) and C(T) at low tip-speed ratios. The agreement weakens with increasing tip-speed ratio, as the wake of turbine enters a reversed flow state. A correction following the philosophy of Maskell is applied to CT in this region, which provides a better agreement.