Axial Flow Fan is different from Centrifugal Fans & Blowers in the method they move the air. An Axial Flow Fan uses a propeller to draw air into it and discharge it, in the same axial directions. However, a Centrifugal Blower draws the air into the inlet side of the blower housing with one of the seven types of wheel. The blower draws the air through the wheels and discharges it at 90 degree. A device that moves air with a propeller is referred to as a Fan, while one with a wheel is called as a Blower.
An axial fan is a type of a compressor that increases the value of pressure of the air flowing through it. Blades of the axial-flow fans force all air to move parallel to the shaft about which the blade rotates. In other way, the flow is axially-in and axially-out, linearly, hence its name. Designing in axial fan revolves around the design of the propeller that generates the pressure-difference and results in the suction force that retains the flow across the fan all time. The main components that need to be studied in the designing include the number of blades and the design of every blade.
The blades are usually made up of Aluminum alloys or Wood. Their application include propellers in Aircraft, Helicopters, Ships and Hydrofoils, Hovercrafts. Also used in wind tunnels and cooling tower. If the propeller is exercising propulsion then its efficiency is the only parameter of interest and rest parameters like power required and flow rate are considered of minimal interest.
Design of Axial Flow Fans:
1. The technique of Inverse Design Problem (IDP) for optimizing the 3-D shape of an axial-flow fan blade based on the desired airflow rate is given.
3. The Geometrical Design of the redesigned fan blade is generated using numerous design variables, which allows the shape of the fan blade to be constructed completely. Thus technique of parameter estimation for the IDP can be used in this study.
4. The result shows that with the redesigned optimal fan blade, the airflow rate of fan can be improved, thereby improving the performance of the Axial-flow fan.
5. Lastly, to verify the validity, the prototype of the real and optimal axial-flow fan blades are fabricated and fan performance test is conducted with these blades on the basis of the AMCA-210-99 standards.
Types of Axial Flow Fans:
Types of axial fans are as follows:
1) Ceiling fans, Table fan, Compact fan, Computer cooling fans, Motor vehicle cooling fans can all be axial fans, depending on the manufacturer.
2) Fan in vehicles such as cars generally prevent the car from overheating by discarding hot air produced by the combustion process in the engine.
3) Same is applied with Computer, where a fan is fitted into the design of the product to prevent it from overheating.
1. Optimal Aerodynamic Design of fan impellers to provide higher efficiency.
2. Reduction in overall weight of the fan, so extending the life of mechanical drive system.
3. It requires lower drive motor rating and light duty bearing system.
4. Low power consumption.
5. Longer life of fans due to improved mechanical strength etc.
6. Lower flow noise and mechanical noise levels compared to the conventional fans.
>> Paint spray booth exhaust.
>> Fume-hood exhaust to exhaust dangerous fumes away from the operator.
>> Welding-fume exhaust in welding booth etc.
>> In process cooling and exhaust of machinery systems.
>> In Spot-cooling of heat generating equipment like generators or transformers.
>> People cooling in hot work areas.
>> To Exhaust heat and cooling of kilns, forges and in steel mills.
>> Boosting of airflow through long duct-work.