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东北农业大学李岩等 偏置叶片对小型垂直轴风力机气动特性影响

【JTS原创论文】东北农业大学 李岩教授团队:偏置叶片对小型垂直轴风力机气动特性影响


      近年来,随着全球生态环境恶化与能源紧缺问题日益突出,清洁可再生能源的开发利用得到了世界各国的广泛关注,风能、太阳能等行业快速发展,尤其是风力发电成为全球商业化利用最好的可再生能源之一。针对中小容量离网型和分布式风能利用的新型风力机研发领域,风力机的一大主要类型——垂直轴风力机得到了世界各国研究者的青睐和关注,尤其是作为升力型垂直轴风力机代表的直线翼垂直轴风力机的研究最受瞩目。但由于其气动特性复杂且研究时间相对较短,还有很广阔的发展空间。在针对直线翼垂直轴风力机的研究中,通过优化风力机自身结构来提高功率和力矩系数的方法被证明是提高直线翼垂直轴风力机气动特性的最有效方式之一。因此,本文从改善风力机自身结构入手,提出了一种将叶片连接到转轴的新方法——偏置叶片法,为改善中小型直线翼垂直轴风力机的气动性能提供了新的思路。


      本文对偏置叶片法在小型直线翼垂直轴风力机的应用进行了数值模拟计算和风洞试验研究。采用NACA 0012、NACA 0018、NACA0024和S 809 4种翼型,研究了叶片厚度和对称性对带有偏置叶片的直线翼垂直轴风力机气动特性的影响,并确定出不同翼型叶片的最佳偏移量,同时对叶片周围的流场变化进行了分析。结果表明,在一个旋转周期内,适当的偏置长度可以改善输出功率特性,并能平滑静态力矩的波动。叶片的最佳偏移长度随翼型而变化,翼型厚度越大,其叶片最佳偏移量也越大。




Abstract


A new way of connecting blade to rotor shaft named offset blade method was proposed for straight-bladed vertical axis wind turbine (SB-VAWT) in this study. In order to invest the efficiency of this method and effects of main parameters including offset length and blade airfoil on improving the output power performance and static starting characteristics, numerical simulations and wind tunnel tests were carried out. Four kinds of blade airfoil including NACA0012, NACA0018, NACA0024 and S809 were selected to analyze the influence of blade thickness and symmetry on SB-VAWT with offset blade. Numerical simulations were firstly carried out on output power for the rotor with 6 kinds of offset length for each airfoil. Wind tunnel tests were also carried out to compare with the results of simulations. The flow fields of rotor with different offset lengths were simulated and the effects of offset blade were analyzed. The optimum offset length among all studied for output power performance was found. Furthermore, the static starting torque and aerodynamic force characteristics of the rotor with optimum offset length were researched. According to the results, appropriate offset length can improve the output power characteristics and smooth the fluctuations of the static torque during one rotational period. The best offset length varies with the airfoil.


(来源:热科学学报)