Optimal Tandem Configuration for Oscillating-Foils Hydrokinetic Turbine
Optimal Tandem Configuration for Oscillating-Foils Hydrokinetic Turbine
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DOI：
10.1115/1.4005423
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发表时间：
2012-03
影响因子：
2
通讯作者：
T. Kinsey;G. Dumas
中科院分区：
文献类型：
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作者：
T. Kinsey;G. Dumas
为了寻求流体动力涡轮机内两个振荡翼片的最佳空间配置，进行了基于2D URANS模拟的数值研究。研究的目的是使涡轮机的功率提取效率最大化。考虑串联空间配置，因为在这种布置中，两个水翼共享相同的流动窗口，这允许涡轮机达到更高的效率。下游翼片在上游水翼的尾流中振荡的相对位置被认为是关键的。实际上，下游翼片和尾涡之间的有利相互作用可能导致意外高的功率提取效率（高达64%），而不利相互作用可能导致下游翼片对提取的总功率产生负面影响。引入了一个全局相移参数来表征级联结构。该参数将箔间间距和运动相移组合成单个项。它被发现是有用的预测额外的有利的配置的基础上已知的结果与类似的上游翼型尾流行为的情况下。提供了与实验数据的比较。在某些情况下，数值预测被认为过度预测了功率提取性能。这可能是由于3D现实中的涡流的2D相干性被破坏，这影响了涡流诱导速度和随后的翼型-尾流相互作用。
A numerical investigation based on 2D URANS simulations is performed in order to seek an optimal spatial configuration for two oscillating foils within a hydrokinetic turbine. The objective of the study is to maximize the power extraction efficiency of the turbine. Tandem spatial configurations are considered because in such arrangement both hydrofoils are sharing the same flow window, which allows the turbine to reach higher efficiencies. The relative positioning of the downstream foil oscillating in the wake shed by the upstream hydrofoil is seen to be critical. Indeed, favorable interactions between the downstream foil and the wake vortices may lead to unexpectedly high power-extraction efficiencies (up to 64%), while unfavorable interactions may cause the downstream foil to contribute negatively to the total power extracted. A global phase shift parameter is introduced to characterize the tandem configuration. This parameter combines the inter-foil spacing and motion phase-shift into a single term. It is found useful to predict additional favorable configurations based on known results for cases with similar upstream-foil wake behavior. A comparison with experimental data is provided. Numerical predictions are seen to overpredict the power extraction performance in some cases. This is likely due to the broken 2D coherence of vortices in the 3D reality which affects the vortex-induced velocities and the subsequent foil-wake interactions.