节点文献

小型风力机设计及风轮气动性能的数值研究

The Small Wind Turbine Design and Numerical Simulation of Aerodynamic Performance for Rotor

【作者】 李常

【导师】 梁武科; 赵道利;

【作者基本信息】 西安理工大学 , 水利水电工程, 2010, 硕士

【摘要】 本文以10KW小型定桨距风力机为研究对象,利用Fluent流体计算软件,对风力机专用翼型及风轮的气动特性进行了数值模拟研究。主要完成了以下几方面的工作:分别选用S-A.RNGκ-ε、κ-ωSST三种湍流模型对S827、S832翼型的绕流流动进行了数值计算,通过与实验数据的对比,研究了不同湍流模型对风力机翼型气动性能的预测能力,以确定适合于本文流动问题的湍流模型。采用数值模拟方法分析了NACA和NREL两个系列的五种风力机翼型的气动特性,结果表明:针对S系列翼型,翼型弯度相近时,随着翼型厚度的增大,对应同一攻角的翼型升力系数有所提高,同时翼型上下面的压差阻力也增大,使得翼型的升阻比有所降低,但与薄翼型相比,较厚翼型的最佳升阻比攻角范围较宽;在适当攻角范围内,增加翼型弯度,可以提高翼型的升力系数及升阻比,使得翼型具有较宽的高升阻比范围,但是超过一定攻角范围时,翼型弯度较大的却容易发生流动分离,翼型气动性能下降;NREL风力机专用翼型较传统翼型更能满足气动性能的要求,并且翼型具有较高的能量转换效率。基于Wilson理论进行了10KW小型定桨距风力机叶片的气动设计,考虑了叶尖损失、叶根损失以及轴向、周向干扰因子对叶片最佳性能的影响,基于Pro/E三维造型软件实现了风力机叶片三维模型的参数化建模,构建了风力机叶片及整个风轮三维实体模型,大大提高了风轮设计与造型的效率和精度。最后,在额定工况和十五个非额定工况下对风轮流场进行了数值模拟,计算出不同风速下风力机的功率和效率,验证了本文所采用优化设计方法和数值模拟方法的有效性、可靠性;并对额定工况下风轮叶片的压力和速度分布进行了分析,探讨了三维旋转效应对流动特性的影响。

【Abstract】 In this article, the research work on 10KW small fixed pitch wind turbine and using the CFD software Fluent to investigate the aerodynamic performance of special airfoils and wind rotor in numerical method. These studies mainly consist of the following aspects:Different turbulence models such as S-A、RNGκ-εandκ-ωSST were used to simulate airfoil S827、S832, and the computational results were compared with the experimental data, the predictability of different turbulence models to the aerodynamic performance were investigated, so as to make sure the certain turbulence models which is suitable for the flow problems in this paper.In this article, numerical simulation is used to analyse the aerodynamic properties of five wind turbine airfoils between the two series of NACA and NREL. The results show that:For the S series airfoil, when the airfoil curvature is similar, with the increase of the thickness airfoil, corresponding to the same angle of attack of the airfoil lift coefficient has increased, at the same time, the pressure drag on the airfoil also increased following, makes the airfoil lift-drag ratio decreased. However, when compared with the thin airfoil, the thicker airfoil has the wider range of best lift-drag ratio. Within the appropriate angle of attack, increase the airfoil curvature, can increasing the airfoil lift coefficient and lift-drag ratio, make the airfoil has a wide range of high lift-drag ratio. But beyond a certain angle of attack range, the larger airfoil curvature is prone to occur flow separation. NREL wind turbine airfoil can better meet the requirements of the aerodynamic performance than the traditional airfoils, and the airfoil has a high energy conversion efficiency.Based on the Wilson method, a 10KW small fixed pitch wind turbine was designed, considering various factors such as the tip losses、root of blade losses、axial and circumferential factors on the optimization of aerodynamic performance for the blade. Based on Pro/E 3D modeling software to realize the three-dimensional models of wind turbine rotor, constructed the three-dimensional solid model of the Wind Turbine Blades and rotor, thus enhanced the efficiency and precision of the design and modeling of wind wheel.Finally, the Fluent software was used for numerical simulation for wind turbine at rated wind speed and fifteen other speeds to calculate the wind turbine power and efficiency under different speeds. Approved the validity and reliability to the optimal design method and numerical simulation; analysed the pressure and velocity distribution of wind wheel blade at rated operating conditions, and discussed the three-dimensional rotational effect on the flow characteristics.

节点文献中: