Which type of fan has airflow that is parallel to the shaft?

An axial fan is designed so that the airflow moves parallel to the axis of the shaft. This design allows the fan to draw air in and discharge it in a straight line along the shaft's length. Axial fans are commonly used in applications requiring high airflow rates at relatively low pressures, such as in ventilation systems and cooling applications.

The nature of the airflow being parallel to the shaft distinguishes axial fans from other types of fans. For instance, centrifugal fans move air perpendicular to the axis of the shaft, utilizing a rotating impeller to increase air pressure before the air exits the fan. Similarly, propeller fans, which are a type of axial fan, can also direct airflow along the shaft's axis, but the term 'propeller' typically refers to a specific design and application. Blower fans generally refer to equipment designed to move air or gas at a higher pressure and can encompass both axial and centrifugal types.

Understanding the distinction in airflow direction and application helps clarify why the axial fan is the correct choice in this query.