Principle of Cooling Fan

Cooling fans are widely used. They are air flow in the same direction as the axis of the blades. For example, electric fans and air conditioners outside fans are fans that operate in cooling flow. It is called " cooling flow" because the gas flows parallel to the fan axis. cooling fans are usually used in occasions with higher flow requirements and lower pressure requirements. The cooling fan fixes the position and moves  the air. The cooling flow fan is mainly composed of the fan impeller and the casing. The structure is simple but the data requirements are very high.

When the impeller rotates, the gas enters the impeller axially from the air inlet, is pushed by the blades on the impeller to increase the energy of the gas, and then flows into the guide vanes. The guide vane changes the deflected airflow into an cooling flow, and at the same time introduces the gas into the diffuser tube, further converts the kinetic energy of the gas into pressure energy, and finally introduces it into the working pipeline.

The blades of an cooling flow fan work similarly to the wings of an airplane. However, the latter applies lift upwards on the wings and supports the weight of the aircraft, while the cooling flow fan fixes the position and moves the air.

The cross section of an cooling fan is generally a wing section. The blade can be fixed in position, or it can rotate around its longitudinal axis. The angle between the blades and the airflow or the distance between the blades may not be adjustable or adjustable. Changing the blade angle or pitch is one of the main advantages of cooling fans. A small blade pitch angle produces a lower flow rate, while increasing the pitch can produce a higher flow rate.

Advanced cooling flow fans can change the blade pitch while the fan is running (this is quite similar to a helicopter rotor), thereby changing the flow accordingly. This is called adjustable moving blade (VP) cooling fan.