Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Flow rate (CFM) in a different inlet are & outlet area

  1. Jul 27, 2012 #1
    Hello,

    Here are the knowns:
    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?

    Thanks a ton!
    John
     
  2. jcsd
  3. Jul 27, 2012 #2

    russ_watters

    User Avatar

    Staff: Mentor

    The answer appears to be given in the problem statement: 270 cfm.
     
  4. Jul 27, 2012 #3
    The fan spec is 90cfm per fan. That doesn't mean that 270cfm (3 fans) is what will exhaust out the rear of the unit. If I have a huge fan inside a box and a very little inlet or outlet, the fan will be choked and pressure will build due to the open air restriction.
     
  5. Jul 27, 2012 #4

    russ_watters

    User Avatar

    Staff: Mentor

    You'll need to look at fan curves and estimate pressure drop through your system then.

    Do you have a sketch you can upload?
     
    Last edited: Jul 27, 2012
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Flow rate (CFM) in a different inlet are & outlet area
  1. Flow rate and valves (Replies: 17)

  2. Flow rate (Replies: 18)

  3. Flow rate of sand (Replies: 1)

Loading...