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Fluid heat transfer problem, please advise. Thanks

  1. Jul 25, 2010 #1
    Air with temperature of 80 F is forced with a speed of 30 m/s through a copper tube with length of 1 meter and inner diameter of 2 millimeters. The copper tube has a temperature of -50 F.

    I want the air coming out of the tube to have a temperature of less than 0 F. Is my design enough or does the tube need to be longer? How do I calculate what the outcoming air temperature will be?

    I need to know this for a medical application so please advise. Any useful equation would be helpful too.

    Also, what is the required PSI of air in order to force it through said tube?

    Thanks in advance.
  2. jcsd
  3. Jul 25, 2010 #2
    Both the pressure required and the heat rate depends on the texture inside the tube.

    The heat can be modeled with a differential equation (although an accurate model may be complex and not possible to solve analytically).

    Then again the pressure and transfer rate affect each other each in their turn, so its a bit tricky. The best way to do it is experiment, although if I had to guess I would say it won't work with the numbers you gave, because the air will spend 1/30th of a second inside the tube and although the volume/surface area is high (2mm is pretty narrow) I don't think you'll drop 80 degress F
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