Aerodynamic blockage and tip-loss effects in a multi-rotor vertical axis wind turbine system

Peter Jamieson提出了一种新型的多转子系统（MRS）。该设计的特点是四个500kW的达瑞厄斯h型垂直轴涡轮机相互顶部，高展弦比（5:1）和45度相异。其中的24个柱子将彼此并排放置，反向旋转，并以四组为一组，在组之间和整个系统周围提供结构支撑。这个系统可能有很多好处。非相位vawt将平滑所经历的扭矩。96台涡轮机只需要24台发电机。选择对称的叶片将允许VAWT单元旋转任何一个方向，只需颠倒安装。反向旋转将从尾流效应中产生能量，并减少整个系统的净扭矩。模块化的特性将简化生产，并允许大部分涡轮机继续运行，如果一个涡轮机故障。既不存在局部偏航，也不存在全局偏航，预计该系统将漂浮在三浮子上。本博士的工作将是堵塞和尖端损失效应。空气动力阻塞效应有望增加功率，也许VAWT的转子两次通过风会增强功率。它还应该通过支撑结构来增强，从而进一步集中气流，因为它与转子在一条线上，而不是像hawtms一样在它们后面。一个关于如何最好地优化功率增强的指南将会产生。高展弦比可能会降低叶尖损失的重要性，然而，来自上方/下方和一侧/两侧的叶尖损失涡的相互作用会带来额外的复杂性。如果时间允许，尾迹效应可以简要分析。

A novel multi-rotor system (MRS) has been proposed by Peter Jamieson. The design features a column of four 500kW Darrieus H-type vertical axis turbines atop each other, of high aspect ratio (5:1) and 45 degrees out of phase. 24 of these columns will be placed alongside each other, counter-rotating and in groups of four, with structural support between groups and around the whole system.The system may have many benefits. The out-of-phase VAWTs will smooth the torque experienced. For 96 turbines, only 24 generators will be required. Choosing symmetrical blades will allow VAWT units to rotate either direction simply by fitting upside-down. The counter-rotation will have energy production benefits from wake effects, and reduce the net torque on the overall system. The modular nature will ease production, and allow much of the turbine to continue operating should one turbine fail. Neither local nor global yawing will be present, and the system is expected to be floating on a tri-floater. The work of this PhD will be on blockage and tip loss effects. A power increase is expected from aerodynamic blockage effects, perhaps enhanced by the rotors of a VAWT passing the wind twice. It should also be enhanced by the support structure causing further flow concentration, as it is in-line with the rotors, rather than behind them like a HAWT MRS. A guideline on how best to optimise power enhancement will be produced.The high aspect ratio is likely to reduce tip loss significance, however there are additional complexities from the interaction of tip loss vortices from above/beneath and on one/two sides. Time permitting, wake effects may be briefly analysed.