axial fan| A fan is a fan whose blades push air to flow in the same direction as the shaft when working | Fan.
According to the classification method of the direction of the air pushed by the blades and the direction of the axis, the cooling fans can be divided into: axial fan, centrifugal fan (the air intake is along the axis direction, but the air outlet is perpendicular to the axis direction), cross flow (Cross-flow) fan (the air intake and air outlet of this fan are perpendicular to the axis), mixed flow fan (the air intake of mixed flow fan is along the axis, however, the gas outlet is along the diagonal direction of the axis and the vertical axis).
Axial fan | air supply form of fan. The most widely used form is to use the axial flow fan | fan to blow down. The reason why it is so popular is that the comprehensive effect is good and the cost is low. In addition, there is the reversal of the direction of the axial fan into the form of upward ventilation, which seems to have become more and more common recently.
The difference between the two forms of air supply lies in the different forms of air flow. When blowing, turbulent flow is generated, and the wind pressure is large but vulnerable to resistance loss. When pumping, laminar flow is generated, and the wind pressure is small but the air flow is stable. In theory, the heat transfer efficiency of turbulent flow is much greater than that of laminar flow, so it has become the mainstream design form. However, in some heat sink designs (such as too tight fins), the airflow is greatly hindered by the heat sink, and the use of ventilation may have a better effect.
How to judge which air supply method to use? Generally speaking, when the heat in the equipment is relatively scattered and evenly distributed, and the wind resistance of the cooling surface is relatively small, exhaust cooling is usually used; when the heat distribution in the equipment is uneven, the wind resistance is relatively large, In the case of more components, blast cooling is usually used. When necessary, the fans can be connected in series (to increase the wind pressure), in parallel (to increase the air volume) or in combination (the operation of cooling fans in parallel and series "is described in the article).