CFM calculation with a known fan and different inlet and outlet areas

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SUMMARY

The discussion centers on calculating the CFM (Cubic Feet per Minute) in a system with specific inlet and outlet areas. The known parameters include an inlet open area of 17 inches², an outlet open area of 30 inches², and three internal fans rated at 90 CFM each, totaling 270 CFM. The consensus is that while the inlet area is relatively small, it is feasible for the fans to achieve the rated CFM, but additional factors such as pressure dynamics and airflow resistance must be considered to determine if the fans will be choked.

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JohnPinnacle
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Hello,

Here are the known's of a chassis:
Inlet open area = 17 inches^2
Outlet open area = 30 inches^2
Internal Fans = 270 cfm (3 fans @ 90 cfm each)

What is the CFM through the system and what's the equations used to figure this out?

I assume that if we had a very small inlet or outlet open area the pressure will build and decrease the CFM. I want to know if my fans will be choked or if they will run at 270cfm.

Thanks a ton!
John
 
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There's just no way to answer your question with any certainty given the small amoutn of information you've provided. Personally I don't think it would be particularly difficult to flow 270 cfm through 17 in^2, but it depends on a lot more than just area.
 

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