Airfoil group for megawatt-class wind turbine blade

The invention relates to an airfoil group for a megawatt-class wind turbine blade, which comprises seven airfoils for the megawatt-class wind turbine blade. The relative thicknesses of the seven airfoils are 0.15, 0.18, 0.21, 0.25, 0.30, 0.35 and 0.40 respectively; the thicknesses of trailing edges of the airfoils are 0.5 percent C, 0.45 percent C, 0.5 percent C, 0.9 percent C, 1.7 percent C, 2.4percent C and 3.0 percent C respectively; and C is the chord length of each airfoil. Compared with the conventional airfoil, the airfoils have a higher maximum lift coefficient, a high design lift coefficient, a higher lift-drag ratio and a higher Reynolds number characteristic. The insensitivity of the maximum lift coefficient to roughness of the airfoils which have the relative thicknesses of 0.15 and 0.18 and are used for the outer side of the blade is respectively 0.049-0.076 and 0.052-0.095 in the Reynolds number range of all tests, which is superior to or equivalent to similar airfoils in foreign countries.