heat transfer coefficients

[hungrychemE]

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

 

[Latexman]

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

 

[25362]

Radiation+convection ht coefficients from horizontal black pipes depend on their temperature, diameter, and [Δ]T 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 80^oF in rooms (still air) I took from one source:

[Δ]T, ^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