考虑小攻角影响立轴风轮气动性能改善方法

立轴风力机叶片在旋转1周中其攻角正负转化,在0°和180°方位角攻角为零,表现为负力矩,这降低了叶片的平均力矩,也降低了升力型立轴叶轮整体性能.首先概述了升力型立轴叶轮的研究现状,分析指出目前的研究均主要针对叶轮整体机构、叶片结构及流场情况进行大攻角高性能区域的改善,未减轻小攻角区域的影响.针对此问题,提出了2种考虑小攻角影响的立轴风轮气动性能改善方法,干扰气流方法和新变桨方案.前者主要消除0°和180°位置角零攻角和负力矩,后者通过改变高性能区的范围来减小特殊位置角的影响并产生新的性能极大值点.基于叶素动量理论,建立双盘面多流管模型,分别运用于NACA0012翼型、旋转半径为2 m的2叶片Φ型、H型立轴风力机,并且采用Matlab程序设计语言进行相应计算研究.研究结果显示这2种方法大幅度地降低了负力矩影响范围,整体效果改善显著,上盘面都优于下盘面.

Enhancement approaches of aerodynamic performance of lift-type vertical axis wind turbine considering small angle of attack

The azimuth angles of 0° and 180° are zero and the torques of both azimuth angles of vertical wind turbine are negative during the blade rotating in a circle with angle of attack in the conversion of positive and negative as well, thus reducing the average torque of the blade and the overall perfor-mance of the lift-type vertical axis wind turbine. This paper summarized the research status of performance improvement of the lift-type vertical axis wind turbine nowadays, pointed out that the current research was mainly aimed at improving the high-performance area of the big angle of attack in the impeller overall body, blade structure and flow field situation instead of reducing the impact of small angle of attack area. In order to solve this problem, two methods of improving the aerodynamic performance of vertical axis wind turbine considering the effect of small angle of attack are proposed: the interference airflow method and the new variable-pitch strategy. The former mainly eliminates the 0 ° and 180 ° azimuth angles of the zero angle and the negative moment, the latter reduces the influence of the special azimuth angle by changing the range of the high performance area and produces a new performance point. Double disk multi-flow tube model is established based on the blade momentum theory. It is applied to the NACA0012 airfoil, the two-blade Φ type and the H-type vertical wind turbine with the rotation radius of 2 m, and the corresponding programming is calculated by Matlab programming language section. The results show that these two methods greatly reduce the negative torque range and the overall effect is improved significantly, and the up disk is better than the down disk.