叶片前缘偏转对H型垂直轴水轮机性能的影响

为提高传统直叶片升力型（H型）垂直轴水轮机的获能效率,提出一种带前缘可偏转叶片的新型垂直轴水轮机,利用计算流体力学（CFD）方法,结合重叠网格和动网格技术对这种新型垂直轴水轮机叶轮的水动力性能进行系统的数值模拟计算,分析不同叶尖速比下带前缘偏转叶片的垂直轴水轮机绕流流场,从而探究前缘偏转角度和偏转长度对这种水轮机动力性能和获能效率的影响规律。结果表明,根据叶片旋转到不同位置时实施前缘偏转可改变来流攻角从而减缓或抑制叶片吸力面的流动分离,有效改善其动态失速特性,进而使H型垂直轴水轮机的水动力性能和获能效率得到明显提升。研究发现,低叶尖速比下这种改善效果最为显著,可拓宽H型垂直轴水轮机高效运行的工作范围。

EFFECT OF VARIABLE DROOP LEADING EDGE ON HYDRODYNAMIC CHARACTERISTICS OF H-TYPE VERTICAL AXIS HYDRAULIC TURBINE

This paper aims at improving the efficiency of the H-type vertical axis hydraulic turbine by using the blade with variable droop leading edge. The two dimensional URANS numerical simulations were conducted, and the hydrodynamic performance of this new type of vertical axis hydraulic turbine was numerically simulated by combining overset mesh and dynamic mesh. The performance of the vertical axis hydraulic turbine with the variable droop leading edge at different tip speed ratios was analyzed, and the effects of the flap angle and flap length on the power-extraction efficiency of the vertical axis hydraulic turbine were also studied. From the simulation results, it could be seen that when the blade rotates to different positions, the variable droop leading edge could change the angle of attack and the flow separation on the suction surface was reduced. The dynamic stall characteristics of the blade could also be improved. The variable droop leading edge is proved to be beneficial to the power generation, and especially at lower tip speed ratio, the operating range of the H-type vertical axis hydraulic turbine is expanded.