In this paper, the effect of the number of blades on the optimal energy utilisation efficiency for a modified Savonius rotor with rotor diameter of 4 m is investigated by computational fluid dynamics simulation using a uniform test method. The appropriate computational domain of a numerical model is determined by first analysing the relative error of the outlet wind velocity on the outflow boundary of the domain. Taking the rotor rotation speed, the blade width and blade installation angle of the modified Savonius rotor as three key factors, it obtains the optimal energy utilisation efficiencies for the modified Savonius rotors with eight, nine and ten blades by transient numerical simulations under the condition of wind velocity of 8 m/s. The sliding mesh and the Piso (pressure implicit with splitting of operators) scheme are utilised in Fluent software simultaneously. The results demonstrate that the optimum wind energy utilisation efficiency rises and the corresponding blade width decreases with the number of blades.

中文翻译：

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叶片数对改进的Savonius转子的最佳能效产生影响

本文采用均匀试验方法通过计算流体动力学模拟研究了叶片数目对转子直径为4 m的改良Savonius转子的最佳能量利用效率的影响。数值模型的适当计算域是通过首先分析出口风速在域的流出边界上的相对误差来确定的。以改进的Savonius转子的转子转速，叶片宽度和叶片安装角度为三个关键因素，通过在以下条件下的瞬态数值模拟，获得了具有八个，九个和十个叶片的改进型Savonius转子的最佳能量利用效率。风速为8 m / s。在Fluent软件中同时使用了滑动网格和Piso（带操作符拆分的隐式压力）方案。结果表明，最佳风能利用效率随着叶片数量的增加而增加，相应的叶片宽度减小。