Hello,

You can calculate it using Nusselt number,

"Nu=h*d/K" where h (Conv. heat transfer co-efficient) will be unknown, d will be diameter over which air flows, and K will be Conductive heat transfer co-eff of Air, and Nusselt number will be calculated based on relation between Nusselt and Reynold's Number, that depends on whether the air flow is laminar or turbulent.

I hope this helps.

Dear Harshil P Raval

Thank you so much for your response.

The flow is laminar, which relation are you exactly talking about between the Nusselt and Reynolds numbers?

I'm talking about these equations for laminar flow:

Nu = (h*d/K) = 0.331*Re^(1/2)*Pr^(1/3) (but this is for the flow over flat plate)

Also find the attached Image containing Nusselt Number for Spherical and Cylindrical components.

Reference - "Heat Transfer by Yunus A Cengel"

Hope this helps you.

Harshil P Raval

Thank you, your response was very helpful.

Much appreciated.