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Nusselt Number dimension question

  1. Sep 8, 2012 #1
    So, in

    Nu=[itex]\frac{hD}{k}[/itex]

    h is the heat transfer coefficient, and D is the diameter of the pipe in which heat transfer takes place...

    ..but what are the dimensions of k in terms of mass (M), length (L), time (T) and temperature ([itex]\theta[/itex])?

    So far, I've worked out that the units for h are J/(m2 hr C), but I'm having difficulty expressing k in terms of what is given.

    Am I wrong is thinking that J/(m2 hr C) can be expressed as W/(m2 K)? I'm thinking that this is relevant to the end units of k, but I am unsure if the dimensions are correct.
     
    Last edited: Sep 8, 2012
  2. jcsd
  3. Sep 11, 2012 #2
    The Nussult number is dimensionless, so if you already know the units of h and D, then the units of k should be obvious: J/(m hr C)
     
  4. Sep 11, 2012 #3
    We could do some major dimensional analysis with this to prove it, but I really don't feel like it. I'm guessing you've done the old pi theorem already though?
     
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