220V Cooling Fan appearance design

    "220V Cooling Fan" fan: the fan blades on the market the more common section curves, general Zhukovsky function Joukowski proposed wing design is based on cross-sectional curve, then in accordance with design requirements, according to the blade root and ends with the rotation the angle between the axis of the roots and the ends of the width of the data, such as rotating stack to form a three-dimensional curved blades and curve fitting, and ultimately complete the blade model design.
"220V Cooling Fan" blade pitch: the distance between the blades is too small, will cause air turbulence, increasing the friction surface of the blade, reducing the efficiency of the cooling fan; the distance between the blades is too large, it will lead to pressure loss increases, insufficient pressure ???
"220V Cooling Fan" blade curvature: in a certain range, the greater the curvature of the fan blades, at the same speed, the greater the kinetic energy of the gas, i.e., the larger the air volume and pressure; same time, the greater the drag blades, requires greater motor torque. When the ratio of the high arc / chord length of more than 0.1, it is no longer lift coefficient increases linearly, so "certain range" that 0.05 <arc height / chord <0.1.