Nusselt Number dimension question

  • Thread starter Jasones
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Main Question or Discussion Point

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.
 
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Answers and Replies

  • #2
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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)
 
  • #3
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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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