An axial pump is one kind of the dynamic pump type. This pump serves to push the working fluid in a direction parallel to the axis/shaft impeller. Different from the centrifugal pump which the fluid output direction is perpendicular to the axis of the impeller.
The mechanical energy generated by the driving source is transmitted through the impeller shaft to drive the pump impeller. The impeller rotation gives the axial force to drives the fluid and produce kinetic energy. In some axial pump designs, there is mounted blades at the stator side, forming a diffuser at the pump outlet. Its function is to remove the rotating effect of the working fluid and to convert the kinetic energy contained, into working pressure.
Axial pumps are used on systems that require high fluid flow discharge, with low head requirement. This type of pump is widely used in irrigation systems, flood prevention pumps, and in steam power plants are used to supply seawater as a cooling medium in condensers.
Here are some comparison between axial pump with centrifugal pump:
- As seen from the efficiency curves, centrifugal and axial pumps have almost the same maximum efficiency levels.
- If the fluid flow decrease, the input power for the centrifugal pump becomes decrease too. But at the axial pump the input power goes up to maximum when the fluid flow stops.
- The axial pump may cause overload at the motor drive if the flow rate is drastically reduced from its design capacity.
- Head generated by centrifugal pumps are much higher than axial pumps.
- On an efficiency curve beyond its maximum efficiency, the axial pump has a lower efficiency level than a centrifugal pump.