Axial flow is the flow of air in the same direction as the axis of the blade.  Centrifugal. Air is thrown out by centrifugal force.  The flow direction of the wind is parallel to the axis, which is called the axial flow fan, (such as the smoke exhaust fan of fire fighting) and conversely is the centrifugal fan, (such as the fan coil fan).  The fundamental difference between axial fan and cabinet centrifugal fan lies in the mechanical structure of the fan:  

The blade diameter of axial flow fans is limited to the diameter of the shell, while centrifugal fans have no limitations in this respect. They can use forward-leaning or forward-leaning blades to meet wider requirements of air volume and pressure.  And muffler processing can be done inside cabinet, there is very obvious advantage on noise index

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