Research On The Effect Of Surface Roughness Of Wind Turbine Blade On Aerodynamic Performance

Wind turbines operate in the natural environment for a long time,and the surface of the blades is affected by various environmental factors,causing changes in roughness,resulting in decreased blade performance and reduced wind turbine efficiency.In this paper,the effect of surface roughness on blade aerodynamic performance is studied,and numerical simulation and wind tunnel experiments are carried out.In this paper,three airfoils of the same series are selected,which are NACA4412,NACA4415,NACA4418.Based on the surface roughness of the blades in actual operation,five kinds of rough models are designed,including uniform roughness,rectangular strip,double rectangular strips,arc-shaped strip and pit model.The rough model is modeled and meshed in ICEM.The flow field simulation model of each rough model was analyzed by Fluent software.The influence of installation position,distribution form and size of roughness on aerodynamic performance is discussed.In addition,the influence of Reynolds number on roughness sensitivity is analyzed.Selected at lOm/s wind speed,-6°-13° angle of attack,the lift coefficient,drag coefficient and lift-to-drag ratio of each model were obtained.The result is as follows:when the rough height is 0-1 mm,the performance degrades drastically.When the height is more than 1mm,the effect is weakened.The performance of the strip at the leading edge is the largest,and the farther away from the leading edge,the smaller the influence,and effect of the double-strip is reduced with the increase of the spacing.Arc stripe has greater effect when the maximum thickness is close to the leading edge.The pit has the greatest influence on the leading-edge suction surface,and the influence of the depth increase is smaller.In each rough model,the increase of angle of attack will increase the effect of roughness,while the increase of Reynolds number will reduce the roughness sensitivity.Wind tunnel experiment is carried out on the NACA4415 model.Experiments on the rectangular,double-rectangular and arc-shaped strip models are performed with reference to the rough model in the numerical simulation.Compared with the results of numerical calculation,the overall trend is the same,the error is small,the lift coefficient measured by the experiment is slightly smaller,and the drag coefficient is slightly larger.The experiment verifies that the numerical simulation roughness has certain reliability.Compared with the traditional roughness model,the five models reflect the influence of roughness on the aerodynamic performance well.The work of this paper combines numerical simulation and experiment.The simulation of roughness has applied a variety of models and obtained qualitative results under each condition.It provides an effective method for the study of the influence of roughness of the wind turbine blade,and provides a certain reference value for the design,operation and maintenance of the blade.