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heat transfer coefficients

heat transfer coefficients

heat transfer coefficients

(OP)
Hi,

I am trying to calculate the rate of condensation of Propane vapor at night in a carbon steel pipe due to temp drop.  Is there any link that would show me the heat transfer coefficient for the propane? I would also need the heat transfer coefficient for butane (same situation).  In addition to this I would like to find out the convective heat transfer coefficient for light wind on carbon steel pipe.  

Thanks alot

RE: heat transfer coefficients

Ambient air on the outside and condensing hydrocarbons on the inside.  Hmmmmmmm.  I think the heat transfer coefficient on the outside will be controlling, so I suggest you shift your focus to that.  A value for condensing HCs of 100-150 Btu/hr/ft"2/F seems reasonable, but it doesn't really matter because the htc of air on the outside will be an order of magnitude lower.

Good luck,
Latexman

RE: heat transfer coefficients


Radiation+convection ht coefficients from horizontal black pipes depend on their temperature, diameter, and ΔT with their surroundings. Enhancing effects such as by wind or a clear sky at nights may increase these values.

Indicative values (Btu per hr.ft2.oF) for pipes at 80oF in rooms (still air) I took from one source:

ΔT, oF →                100    200   400
 
pipe dia., in.

      4                       2.2   2.7    4.0
      8                       2.1   2.6    3.9  
     12                      2.0   2.5    3.8

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