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现代大型风力机在工作时叶片经历大变形与振动,将会对其周围的动态流场产生影响,从而导致气动力的改变。因此有必要深入研究风力机翼型在复合运动情况下的动态失速气动特性,以正确预测大型风力机运行时的载荷。该文应用计算流体力学方法,对S809翼型在不同运动形式下的动态失速特性进行了二维数值分析。首先对翼型在作俯仰运动下的轻失速和深失速情况分别结合S-A、SST k-?和RSM三种湍流模型进行了动态失速数值模拟,结果表明S-A、SST k-?和RSM三种湍流模型都能有效地计算出翼型的气动力。然后采用SST k-?模型仿真了翼型在挥舞运动、俯仰摆振耦合运动下的动态失速气动特性,并与相同工况条件下翼型作俯仰运动时的气动特性进行了对比分析。发现翼型在挥舞运动下的动态失速虽然弱于俯仰运动,但其强度不容忽视;而翼型在作俯仰与摆振耦合运动时比单纯作俯仰运动时的失速程度更深。因此在风力机设计阶段为获得保守的气动载荷预测,有必要将叶片截面在挥舞与摆振方向的运动转换成等效攻角,叠加在主攻角上进行动态失速气动力计算。
Modern large-scale wind turbine blade in the work experience large deformation and vibration, it will have dynamic flow around its impact, resulting in changes in aerodynamic. Therefore, it is necessary to study the aerodynamic characteristics of the dynamic stall of wind turbine airfoils under complex motions in order to correctly predict the load of large-scale wind turbine during operation. In this paper, two-dimensional numerical analysis of the dynamic stall characteristics of the S809 airfoil under different motions is carried out by computational fluid dynamics. Firstly, the numerical simulation of dynamic stalling with light stalls and deep stalls under airfoil pitch is carried out respectively with three turbulence models SA, SST k-? And RSM. The results show that SA, SST k-? And RSM are three kinds of turbulence The aerodynamic forces of the airfoils can all be calculated effectively by the model. Then, the aerodynamic characteristics of the dynamic stall of the airfoil coupled with waving and pitching vibration are simulated by using the SST k-? Model. The aerodynamic characteristics of the aerofoil with pitching motion under the same working condition are also analyzed. It is found that the dynamic stall of the airfoil is less than the pitching motion but its strength can not be ignored. The aerofoil is more decelerated than the pitching motion when the airfoil is coupled to pitch and shimmy. Therefore, in the wind turbine design stage, in order to obtain the conservative aerodynamic load forecast, it is necessary to convert the blade cross-section in waving and shimmy direction to the equivalent angle of attack, superimposed on the main angle of attack for dynamic stall aerodynamic calculation.