answer:A centrifugal fan? In a laptop? Do tell. On large industrial projects we do use “centrifugal” fans. They’re a real thing. But that’s a huge fan (in our case, that is, in power boilers) mounted in duct moving air (or gas) in the direction of flow as indicated on the engineering drawings and required for the process. The fans we typically employ on a utility-class power boiler are bigger-than-room-size, meaning the fan itself is bigger than a room in a house, and the motor half as big as that. This is also commonly referred to as a blower fan. (Also common enough – though smaller! – in residential, industrial and HVAC and other such applications where air movement is through ducting. (Centrifugal pumps work the same way, in principal.) But the fans that I’ve ever seen in desktop or laptop computers are not of that type. They are what is called an “axial type” fan (just like on a room or desktop fan). In this case the fan blades turn at right angles to the direction of the air flow. (Either forward or backward.) In that case, turning an axial fan around (assuming there are no changes made to the drive system or electrical connectors!) would reverse the flow of air. However, if you turn the fan around by also change the wiring leads, then – if the fan operates at all! – it may continue to turn in the same direction as before the reorientation, if the motor will run in reverse. (Probably not likely with a cheap laptop fan, but not to be fully discounted either.)