Numerical simulation method of influence of PTFE-based membrane on aerodynamic characteristic of wind turbine blade

A numerical simulation method of an influence of a polytetrafluoroethylene (PTFE)-based membrane on an aerodynamic characteristic of a wind turbine blade, wherein numerical simulation computation is performed on influences of a PTFE-based nano functional composite membrane on aerodynamic characteristics and entire aerodynamic performance of a blade airfoil after pasting and covering the surfaces of blades of a large horizontal axis wind turbine by using a hydrodynamic computation method, which comprises the following steps:

• (1) selecting two blade airfoils;
• (2) determining that wind energy capture areas of a blade are located in middle and tip areas of the blade, selecting chord length positions and angle of attack ranges of the two airfoils according to respective spreading position and chord length distribution direction, and meanwhile selecting Reynolds numbers for aerodynamic characteristic computation of the airfoils;
• (3) selecting a PTFE-based nano functional composite membrane with a maximum thickness of 0.26 mm and a surface roughness of 0.18 μm;
• (4) solving a two-dimension incompressible Navier-Stokes equation by using a finite volume method, wherein the computation state is a steady state, turbulence simulation adopts an SST k-ω model, the computation grid of the airfoil adopts a C-shaped structure grid, and the height of the first-layer grid of the surface of the blade satisfies y+≈1 (the first layer is a bottom layer, and y+ represents a thickness, and 1 represents a precision);
• (5) geometrically modeling, and spreading the boundary of the airfoil along a normal direction by the same distance as a membrane thickness to obtain a new computational geometry;
• (6) performing influence number simulation computation, wherein the action point of a moment is selected at the position of ¼ chord length of the airfoil, so that the rise moment of the airfoil is positive, and the bow moment of the airfoil is negative,
• an airfoil lift coefficient is
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• a drag coefficient is
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• a pitching moment coefficient is
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• (7) comparatively analyzing changes in aerodynamic coefficients of two wind turbine generator blade airfoils before and after being pasted and covered with the PTFE-based nano functional composite membrane to obtain influence number simulation computation results.