Centrifugal "Micro Cooling Fan"
When working the centrifugal fan, the air to push the blade axis perpendicular to the direction (i.e., radial) flow, the intake air is in the axial direction, while the outlet was perpendicular to the axial direction. In most cases, the use of axial fan cooling effect can be achieved, however, and sometimes if you need to rotate 90 degrees exhaust airflow or need a larger pressure, we must use the centrifugal fan. Fan strictly speaking, it is also a centrifugal fan.
Features: limited flow rate, high pressure
Francis "Micro Cooling Fan"
Also known as the diagonal flow fan Francis fan, first glance, Francis fan and axial flow fan is no different, in fact, Francis fan intake is along the axis, but the outlet is a diagonal direction of the axis and vertical axis. Because this fan blades and housing, said conical, thus resulting in a high pressure, in the same size and other comparable performance under, compared with axial fans, centrifugal fan noise lower.
"Micro Cooling Fan" characteristics: high flow rates and relatively high pressure