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Fans
Posted: Thu Dec 13, 2007 1:19 pm
by ian.stewart
one of these silly questions, just been thinking, for example if you run a computer fan at a set speed and moves 200cfm, if you bolt a second identical fan to the first, assuming there are no leaks between the housings and, run them both at the same speed and same direction would you move more air, less air or the same amount, would a airgap between the two fans have any effect on the results ????
Ian
Posted: Thu Dec 13, 2007 2:00 pm
by kiwicar
If you run two fans as you describe, then they will flow the same quantity of air (provided they do actually run at the same speed as the previous single far) the reality is that they will both run faster than a single fan and flow more, but also draw more current. The whole set up will not flow as much as the two fans side by side.
leaving a gap between them that is open to the outside world will reduce the flow. Spacing the fans apart in a common duct that is closed to the outside would probably improve flow over a short range of distance between the fans, adding flow straiteners in the gap between would increase flow (and eficiency)
Mike