Forced convection heat transfer problem

[HugoR]

This is a forced convection heat transfer problem and would appreciate any help!

Stack of steel billets is placed in a cooling chamber. All billets of the same row are touching each other and each row is spaced of 5 in. I want to calculate the convection coefficient and pressure drop across the bundle. Ultimately, I would like to calculate the heat transfer after 1 hour (billets temperature and heat loss)

Billets T = 1100 F
Air, v = 60 ft/s, T = 70 F


T = 1100 F ______________
OOOOOOOOOOO <--
OOOOOOOOOOO
OOOOOOOOOOO <-- Air, v = 60 ft/s, T = 70 F
OOOOOOOOOOO
OOOOOOOOOOO <--

____________________________


What I am thinking of is to calculate an average h because air velocity is very high between the billets but a stagnant zone will exist near the hollow of adjacent billets.

I don't know the governing equations and how to start this problem.

Thank you if you can help.
HR

 

[siddharth]

I think there are experimental correlations available for the nusslet number and pressure drop for flow over bundles of tubes, depending on how many rows are in the direction of the flow.

For example, see Heat Transfer: A Basic approach by M.Necati Ozisik, McGraw-Hill, pg 384-404

 

[Mapes]

This is also discussed in Incropera and DeWitt's Fundamentals of Heat and Mass Transfer.