摘要
H型垂直轴风力机利用机翼叶片的升力作用来驱动叶轮的转动,在叶片转动一周的过程中,机翼上的攻角随时发生变化,因此其气动原理与水平轴风力机有很大不同。本文先总结了H型垂直轴风力机的升力理论,得出风力机功率的公式,初步分析出风力机运转的一定规律,分析了在不同尖速比条件下机翼上攻角的范围。然后在NACA0012基本翼型的基础上,通过对翼型采用了两种优化方法,一种是将机翼尾缘高压力面切开的方案,;另一种是将翼型沿中线弯曲的方案。通过数值模拟的方式,比较了两种方案机翼功率及启动性能的影响。为寻找优化机翼形成的原因,本文还对最优化的切口方案与原型机翼NACA0012的升阻力系数进行了对比分析,结论表明,在升阻力系数相差不大的情况下,非对称机翼引起的尾迹变化,使得前机翼对下游机翼的干扰变小,是提高整机效率的关键因素,这种优化方式能够提高H型风力机整机效率30%以上。
Lift aerodynamic forces of aerofoil provide the positive driving torques to the rotor of H-type of vertical axis wind turbines（VAWT）.When the blades were in different angle of location,the angle of attack to the aerofoil changed time by time,thus VAWT has different aerodynamic conditions as those horizontal axis wind turbines do.In this paper,we give the theoretical analysis for the H-type of VAWT.Finally,the total power,torque and the thrust,can all be explained by the lift coefficient and drag coefficient.The attack angle was studied in different tip speed ratio conditions.Then,on the basis of the airfoil of NACA0012,use two methods to optimize the airfoil.The first one is cutting high pressure surface in a certain distance away from the trailing edge,the other is bending the airfoil along the center middle curving.By numerical simulation,compare the power of the impact of the optimized airfoil;Simulation results show that the way of chancing airfoil to improve the power and Low wind speed torque method is feasible,and the different ways of the optimization to improve different aspects of airfoil performance.
出处
《流体机械》
CSCD
北大核心
2012年第10期33-40,共8页
Fluid Machinery
关键词
风力机
空气动力学性能
功率
叶轮优化
数值模拟
vertical axis wind turbine
aerodynamic
power
impeller optimization
numerical simulation
