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A Challenging Thermo Problem

  1. Apr 19, 2005 #1
    Q. The air in a 6m x 5m x 4m hospital room is to be completed replaced by conditioned air every 20 min. If the average air velocity in the circular air duct leading to the room is not to exceed 5 m/s, determine the minimum diameter of the duct.

    We can figure out the volume of the room, knowing the dimensions then what.

    time is given, what else can be done?
  2. jcsd
  3. Apr 19, 2005 #2
    think about volume flow rate...
  4. Apr 20, 2005 #3
    Ok, found out volume flow rate what next
  5. Apr 20, 2005 #4


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    - You have the volume of the room that needs to be replaced every 20 minutes. That should tell you something about the volumetric flow rate needed to come out of the duct.

    - If you have a flow rate, what equation also contains the duct's cross sectional area and it's velocity?

    Those are two pretty big hints there.
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