The key difference between radial flow and axial flow fans is the direction in which air moves relative to the fan shaft. This difference in flow direction leads to different pressure capabilities, efficiency ranges and typical applications in mining and industrial ventilation.
Axial flow fans move air mainly parallel to the shaft. Air enters the fan along the axis, passes through the rotating blades and leaves in the same general direction, like air moving through a propeller. Because of this straight-through flow, axial fans are well suited for high-volume, low to medium pressure ventilation duties. Large vane-axial fans serve as main fans in many mines and tunnels, while tube-axial fans are used as auxiliary duct fans and industrial exhaust fans.
Radial flow fans (often called centrifugal fans or blowers) discharge air in a direction perpendicular to the shaft. Air enters the impeller near the centre, is accelerated outward by centrifugal force and then collected in a spiral casing, or volute, which directs it into the outlet. This radial flow pattern allows centrifugal fans to generate higher static pressures, making them suitable for systems with long ducts, filters, bends and other resistance-increasing components.
Because of these differences, axial and radial flow fans tend to be used in different parts of a ventilation system. In mining ventilation, main axial fans move large quantities of air through shafts and drifts, while radial flow fans may be used in dust collection systems or process exhaust where higher pressure is needed. In industrial plants, axial fans ventilate large spaces and rooftops, whereas centrifugal fans handle high-resistance duties such as baghouse exhaust, furnace draft and scrubber systems.
The difference in flow direction also influences fan shape and layout. Axial fans are typically cylindrical, with the impeller inside a round casing, and can be installed inline with ducts and tunnels. Radial fans have a more compact but wider volute housing, with the outlet turned at 90 degrees relative to the inlet. This can be useful when space is limited or when ductwork must turn sharply, but it also requires careful design to control losses and noise.
In summary, radial flow fans discharge air perpendicular to the shaft and are associated with centrifugal designs and higher pressures, while axial flow fans move air parallel to the shaft and are best for high-volume, low to medium pressure ventilation. Both are essential in mining and industrial systems, but they are applied in different parts of the airflow network based on their flow characteristics.
