The main difference between a cross flow fan and an axial fan lies in how air moves through the fan and the shape of the impeller. These differences affect the pressure range, noise characteristics and typical applications in ventilation, from compact equipment cooling to large mining and industrial systems.
A cross flow fan, sometimes called a tangential fan, uses a long, narrow impeller with many closely spaced blades arranged around the circumference. Air enters along the length of the impeller, flows tangentially across it and exits on the opposite side, often through a long rectangular outlet. The airflow pattern is roughly perpendicular to the shaft, but extended across a wide, shallow section. Cross flow fans produce a uniform curtain of air along their length, which is useful in air conditioners, fan coil units, display cases and other compact equipment.
An axial fan moves air parallel to the shaft. It looks like a propeller inside a ring or cylindrical casing. Air enters the fan along the axis, passes through the rotating blades and continues in the same direction, which is ideal for moving large volumes of air through ducts, tunnels and shafts. Axial fans are the dominant choice for mining main fans, tunnel ventilation fans and many industrial exhaust and supply fans.
Because of their geometry, cross flow fans typically operate at lower pressure and lower efficiency than well-designed axial or centrifugal fans of comparable size. Their strength is in creating a broad, even airflow over short distances in compact equipment. They are rarely used as primary fans in large industrial or mining ventilation systems, where higher airflows and pressures are required and maintenance access must be robust.
Axial fans, by contrast, can be built in very large diameters and achieve high efficiencies in high-volume, low to medium pressure applications. In mines, large vane-axial fans provide main ventilation through shafts, and tube-axial fans ventilate headings via flexible ducting. In industrial buildings, axial roof and wall fans provide general ventilation and heat removal.
In summary, a cross flow fan uses tangential, across-the-impeller flow to create a uniform air curtain in compact equipment, while an axial fan uses straight-through axial flow to move large volumes of air through ducts, tunnels and mines. For mining and heavy industrial ventilation, axial fans are far more common and better suited than cross flow fans.
