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Homework Help: Max possible air flow through a tube

  1. May 5, 2009 #1
    1. The problem statement, all variables and given/known data

    I had a discussion with some of my friends about this matter, but my physics basics related to fluid flow dynamics aren't well enough to draw a conclusion, so here it is:

    On the left side of the diagram is a space with infinite amount of air (breathable Earth air) at pressure of 1 atmosphere, on the right side is infinite vacuum

    Problem - determine maximum possible flow through the restriction (shape is a round tube for the ease) in a given time period - 1 minute and will decrease/increase of the size (D=10mm compared to D=1000mm) be of any significance

    http://img17.imageshack.us/img17/7366/diagram1.gif [Broken]

    the discussion wasn't about increasing the flow by adjusting the shape of the restriction or any other variables, just to determine how much of the air from the left side can travel to the right side in one minute
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. May 5, 2009 #2


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    You are looking for a calculation called an oriface plate flow.
    It only depends on the pressure difference, density, and for a compressible substance (like air) some thermodynamic properties.
    And a constant which depends on the shape of the opening, for a round hole that is much longer than it's diameter this is k=0.82
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