In our daily life, we all come into contact with the cooling fan, and the two important indicators to measure the cooling capacity of the cooling fan are the air volume and air pressure of the cooling fan. So what is the relationship between the air volume of the cooling fan and the air pressure of the cooling fan?

        Air volume refers to the product of the fan ventilation area and the plane speed of the area. The ventilation area is the exit area minus the projected area at the vortex tongue. Plane velocity is the velocity of the gas flowing through the whole plane in meters per second. When the plane speed is constant, the larger the outer diameter of the fan blade impeller, the larger the ventilation area and the larger the air volume. The greater the air volume, the greater the amount of heat absorbed by the cold air, and the more heat can be taken away when the air flows and transfers, and the more obvious the heat dissipation effect is.

        Wind pressure refers to the pressure that the fan needs to generate when it blows air against resistance.It is divided into static pressure and dynamic pressure. Static pressure refers to the pressure measured parallel to the direction of gas flow.Dynamic pressure is the process of converting kinetic energy required for gas flow into pressure [ in mm/H2O ( Inch/H2O ) and how many millimeters ( inches ) of water column of wind pressure ].

        In practical application, the nominal maximum wind magnitude is not the actual air supply volume obtained by the cooling fins, and the large air volume does not mean a strong ventilation capacity. As the air flows, the air flow will encounter the obstruction of the radiating fins in its flow path, and its resistance will restrict the free flow of air. That is, when the air volume increases, the air pressure will decrease. Therefore, there must be an optimal operating point, that is, the intersection of the fan performance curve and the wind resistance curve. At the operating point, the slope of the fan characteristic curve is the smallest, while the rate of change of the system characteristic curve is the lowest.

        The relationship between the air volume of the cooling fan and the air pressure of the cooling fan is mutually restricted and not two isolated performance indicators. The relationship between them is that the air volume decreases with the increase of pressure difference, and the fan blade shape and the overall structural design of the cooling fan determine their degree of restriction.