The reason why the axial flow fan is called "axial flow" is that the gas flows parallel to the fan shaft. It is mainly composed of an impeller, a casing, an electric motor, etc. The bracket is generally connected to the casing duct with steel. The impeller and casing of the anti-corrosion axial flow fan are made of fiberglass, and the others are mostly made of steel plates. When the AC axial flow fan is working, the motor is connected to the AC power and runs, driving the impeller to rotate. When the impeller rotates, the gas enters the impeller axially from the air inlet and is pushed by the blades on the impeller. The working method of the blade is similar to that of an airplane wing. According to the principle of fluid mechanics, the fluid flowing around the blade has a lift on the blade, and the blade gives the fluid an equal and opposite thrust. This thrust does work on the fluid, which increases the energy of the gas. Then the gas flows into the guide vane, which converts the deflected airflow into axial flow, and at the same time introduces the gas into the diffuser, where the kinetic energy of the gas is further converted into pressure energy, and then introduced into the working pipeline, thereby realizing the function of ventilation. The cross section of an axial fan is generally an airfoil section, and its blades can be fixed or rotated around the longitudinal axis, and the angle between the blades and the airflow or the blade pitch can be fixed or adjustable. A small blade pitch angle produces a lower flow rate, while an increased pitch can produce a higher flow rate. Some advanced axial fans can change the blade pitch during operation (similar to a helicopter rotor) and change the flow rate accordingly. This is called a variable blade (VP) axial fan.
