Because of the impeller strength and noise and other reasons, when the circumferential velocity of the impeller outer diameter of the axial flow fan is high, the noise will be greater than that of the centrifugal fan.
The moving blade or guide blade of modern axial fan is often made adjustable, that is, its installation Angle can be adjusted. This not only greatly expands the range of operating conditions, but also significantly improves the efficiency under variable operating conditions. Therefore, its range of use and economy are better than that of centrifugal fans. Especially in recent years, the movable blade adjustable mechanism has been successfully adopted, making axial flow fans increasingly widely used in large power stations (more than 800,000 kW), large tunnels, mines and other ventilation and ventilation devices. In addition, axial fan is also widely used in plant, building ventilation, air conditioning, cooling tower ventilation, boiler ventilation, chemical industry, wind tunnel wind source and so on.
The total pressure efficiency of single-stage axial flow fan can reach more than 90%, and the static pressure efficiency of single-stage fan with diffusion cylinder can reach 80%. Generally, the pressure coefficient of axial flow fans is low, -p <0.3. And flow coefficient -Q=0.3 ~ 0.6. The specific revolution sn of the single-stage axial flow fan is 18 ~ 90 (100 ~ 500). In recent years, axial fan gradually to high pressure development, such as a Japanese power station with Denmark VARIAx movable blade adjustable axial flow fan, its full pressure has reached 14210Pa, therefore, many large centrifugal fans have been replaced by axial flow fan trend.