Critical Stokes Number for Gas-Solid Flow Erosion of Wind Turbine Airfoil

• 作 者: Li Deshun Gong Yuxiang Li Rennian Li Yinran Ma Ruijie
• 机 构: School of Energy and Power Engineering,Lanzhou University of Technology,Gansu Provincial Technology
• 出 处: Transactions of Nanjing University of Aeronautics and Astron
• 发表日期: 2016年01期
• 关键词: wind turbine airfoil erosion critical Stokes number gas-solid two-phase flow

Wind turbine blades are inevitable to be eroded in wind-sand environment,so it is crucial to identify the flow conditions under which the erosion happens.Here,the effect of the sand diameter on wind turbine airfoil is first investigated.When the sand diameter is less than 3μm,the sands will bypass the airfoil and no erosion occurs.When the sand diameter is larger than 4μm,the sand grains collide with the airfoil and the erosion happens.Thus,there must be a critical sand diameter between 3μm and 4μm,at which the erosion is initiated on the airfoil surface.To find out this critical value,aparticle Stokes number is introduced here.According to the range of the critical sand diameter mentioned above,the critical value of particle Stokes number is reasonably assumed to be between 0.007 8and 0.014.The assumption is subsequently validated by other four factors influecing the erosion,i.e.,the angle of attack,relative thickness of the airfoil,different series airfoil,and inflow velocity.Therefore,the critical range of Stokes number has been confirmed.

Wind turbine blades are inevitable to be eroded in wind-sand environment, so it is crucial to identify the flow conditions under which the erosion happens. Here, the effect of sand diameter on wind turbine airfoil is first investigated. less than 3 μm, the sands will bypass the airfoil and no erosion occurs .When the sand diameter is larger than 4 μm, the sand grains collide with the airfoil and the erosion happens.Thus, there must be a critical sand diameter between 3 μm and 4 μm, at which the erosion is initiated on the airfoil surface. To find out this critical value, aparticle Stokes number is introduced here. According to the range of the critical sand diameter mentioned above, the critical value of particle Stokes number is reasonably assumed to be between 0.007 8and 0.014. The hypothesis is again validated by other four factors influecing the erosion, ie, the angle of attack, relative thickness of the airfoil, different series airfoil, and inflow velocity. refore, the critical range of Stokes number has been confirmed.