"DC Fan" air flow: air flow fan ventilated area refers to the product of the speed of the plane. Ventilation area is at the outlet area by subtracting the projected area of the vortex tongue. Speed airflow through the entire plane is the plane of the gas velocity, the unit is m3 / s. Plane speed is constant, the outer diameter of the impeller blades, the greater the ventilation area, the greater the amount of wind. Plane speed is determined by the rotor speed and air pressure. Ventilation certain area, flat rate, the greater the amount of wind. The larger the amount of wind, the greater the heat absorption of air, the air flow can be transferred with a week to take away more heat, fan heat effect is more obvious.