The working principle of low-noise axial flow fan is that when the impeller rotates, the gas enters the impeller axially from the air inlet and is pushed forward by the blades on the impeller, thus increasing the energy of the gas and then flowing into the guide blade.  The guide vane changes the deflecting gas to axial activity, while the guide vane guides the gas into the diffuser, further converting the kinetic energy of the gas into pressure energy, which is introduced into the working pipeline.  The blades work in a similar way to the wings of an airplane, but the latter exert lift on the wings and support the weight of the airplane, while axial fans hold the position and move the air.  The section of low noise axial flow fan is usually the airfoil section.  Blades can be fixed or rotated around their longitudinal axis.