Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Nusselt number

  1. Mar 12, 2008 #1
    Hello I need to calculate the nusselt number for natural gas in a buried pipeline. My question is how to calculate the convective heat transfer co efficient?
    The data is 220000m3/h, pipe ID 35", gas temperature 100C and ground temperature is 4C, gas SG 0.65, k = 0.037 W/m-K, R= 441 J/kg-K, CP = 2016 J/Kg-K, gama = 1.28
     
  2. jcsd
  3. Mar 12, 2008 #2

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    Do you mean the convective coefficient for the outside of the pipeline? Or are you trying to find a temperature distribution inside the pipe?
     
  4. Mar 12, 2008 #3
    I am trying to find temperature distribution inside the pipe. I guess nusselt number associate with the flow of the liquid and it take convective heat transfer co-efficient within the fluid and not between wall and fluid, please correct me if I am wrong.
     
  5. Mar 12, 2008 #4

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    Nusselt number's general description: Dimensionless temperature gradient at the surface of a convection flow (not limited to internal flow).

    There are several methods of dertermining or estimating the thermal distribution in a fluid travelling through a pipe of a different temperature. you will have to decide if the flow if fully developed or if you are within the hydrodynamic entrance region, and what sort of things you can assume about the flow such as incompressible, laminar/turbulent, constant pipe wall temperature, things like that.

    One thing you might look into is the Momentum and Heat Transfer Analogy, a.k.a. the Reynolds Analogy. This analogy can give you an estimate of the fluid's temperature distribution based on its velocity distribution. Otherwise, The differential equation describing the heat flux in the fluid could get you to where you want to go.
     
  6. Mar 12, 2008 #5
    well that is the problem I was not given any diffrential eq. all I was given is the above data
     
  7. Mar 12, 2008 #6

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    Is this a homework problem? Do you have a textbook of some kind that lays out such equations for you?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Nusselt number
  1. Nusselt number For ANSYS (Replies: 14)

Loading...