风力机弯曲叶片附面层流动转捩和分离实验

以柔性叶片能量转换装置为研究对象,在风洞闭口实验段,应用PIV技术测试弯曲叶片附面层速度场,通过速度场分析,得到弯曲叶片几何结构对附面层的流动分离和旋涡运动的规律。叶片的弯曲变形可以减少前层叶片吸力面附面层内的低能流体向空间扩散的范围,因此有助于减少附面层附近因流动分离而产生的升力损失;但对于后层叶片吸力面,由叶片弯曲带来的动态失速涡范围扩大会加剧流场的不稳定性。通过弯曲叶片流场PIV实验,可以指导柔性叶片的选材和设计,为提高叶轮的能量转换效率和运行稳定性提供可靠的实验依据。

Experiment of Flow Transition and Separation on Boundary Layer of Curved Blade on Wind Turbine

The energy conversion device with flexible blades was taken as the research object; in the closed experimentation section of the low speed wind tunnel, velocity field of curved blade boundary layer was tested by PIV measure technology; when camber of the blades was changed, the rule of flow separation and vortex motion on the boundary layer were obtained. The experimental results showed that the bending deformation of blades in the front layer can reduce accumulation and diffusion low-energy fluid on the boundary layer, and it is helpful to reduce the lift loss of the blades due to flow separation; but for the rear layer, flow instability will increase because the dynamic stall vortex near boundary layer extends due to the bending deformation of blades.The flow field analysis of the curved blades can guide material selection and the design of flexible blades, and provide experimental reference for improvement of the energy conversion efficiency and working stability.