Working principle of axial flow fan

When the impeller rotates, gas enters the impeller axially from the inlet, and is then pushed by the blades on the impeller to increase energy, and then flows into the guide vanes. The guide vanes change the direction of the deflected airflow to axial flow, while introducing the gas into the diffuser, further converting the kinetic energy of the gas into pressure energy, and finally introducing it into the working pipeline.
The working mode of axial flow fan blades is similar to that of aircraft wings. However, the latter applies lift upwards to the wings and supports the weight of the aircraft, while axial flow fans are fixed in position and move the air.
The cross-section of an axial flow fan is generally a wing section. The blades can be fixed in position or rotated around their longitudinal axis. The angle or spacing between the blades and the airflow can be either non adjustable or adjustable. One of the main advantages of axial flow fans is the ability to change the blade angle or spacing. The blade spacing angle can produce lower flow rates, while increasing the spacing can produce higher flow rates. Advanced axial flow fans can change the blade spacing during fan operation (similar to helicopter rotors), thereby changing the flow rate accordingly. This is called a Variable Vane (VP) axial flow fan.