Micro Cooling Fan air volume is how come?

And "Micro Cooling Fan" related to the amount of wind is how come? Air volume means the fan-ventilated area and volume of the area of the flat rate. Ventilation area is minus vortex outlet area at the projected area of the tongue. Plane speed velocity of the gas stream through the entire plane, the unit is m / s. Flat rate constant, "Micro Cooling Fan" blade impeller diameter, the greater the ventilation area, the greater the amount of wind. The larger the amount of wind, cold air heat absorption is bigger, can take more heat transfer of air flow, cooling effect is more obvious. Due to air flow, air flow path will encounter in their fins obstruction, its impedance will limit the free flow of air. Namely "Micro Cooling Fan" when the wind increases, air pressure decreases. Therefore, there must be an optimum working point operations, namely the intersection of the fan performance curve and drag the curve. In the operating point, the slope of the fan characteristic curve is minimized, and change the system characteristics curve was the lowest.