B-Spline曲线聚风装置直线翼垂直轴风力机启动性能数值模拟

Numerical simulation of starting performance of vertical axis windturbine with B-Spline curve wind gathering devices

为了提升直线翼垂直轴风力机的启动性能,基于B-Spline曲线生成方法,提出一种具有流线型轮廓的聚风装置,将其分别安装在风轮顶端和底端,用以提升风轮附近的来流风速,使风轮汲取更多风能,达到更易启动的特点.选取聚风装置的5个结构参数进行设计:聚风装置与风轮间隙距离ΔL、底圆半径R_(1)、顶圆半径R_(2)、入口角度α_(1)和出口角度α_(2).设计方法采用二次旋转正交组合筛选最优模型,通过三维数值模拟研究聚风装置参数对直线翼垂直轴风力机启动性能的影响,获得了最佳外形参数组合.此外,对有无加装聚风装置的直线翼垂直轴风力机进行了静态三维数值模拟.结果表明,通过添加具有外凸流线型轮廓的聚风装置,直线翼垂直轴风力机的启动性能有显著提升.在风速较低的情况下,性能改善更加明显.聚风装置可使直线翼垂直轴风力机的平均启动力矩系数最大增加38.8%,峰值平均启动力矩系数最大可增加31.2%.

In order to further improve the static start-up performance of straight-bladed vertical axis wind turbines(SB-VAWT),a wind gathering device(WGD)with convex streamline profile was proposed based on the B-Spline curve generation method.It was installed at the top and bottom of the wind wheel respectively to improve the incoming wind flow velocity near the wind turbine,make the wind wheel to absorb more wind energy and achieve the characteristics of easier start-up.Five design structural parameters were selected for the WGD including:the clearance distance between WGD and wind turbineΔL,bottom circle radius R_(1),top circle radius R_(2),entrance angleα_(1)and outlet angleα_(2).The design method adopted a quadratic rotation orthogonal combination to screen the optimal model.The influence of WGD parameters on the static starting performance of SB-VAWT was studied through three-dimensional numerical simulation,and the optimal combination of shape parameters was obtained.In addition,a static three-dimensional numerical simulation of SB-VAWT with or without WGD was carried out.The results show that the static starting performance of SB-VAWT is significantly improved by adding WGD with convex streamline profile.The starting performance of a SB-VAWT has been significantly improved.Under low wind speeds,the performance improvement is more significant.The WGD can increase the average starting torque coefficient of SB-VAWT by a maximum of 38.8%,and the peak average starting torque coefficient can be increased by a maximum of 31.2%.