# Heat loss of a steel steam pipe

I have a heat transfer question, I work in a plant and am doing a re-insulation project. If an unexposed steel steam pipe (k=47) of diameter 10 inches, maintains an internal temperature of 460F and is exposed to ambient air (70F) flowing at 5 mph across the pipe. Determine the heat loss per unit length. The inside diameter of the pipe is 9.224 inches and the O.D. is 10.75 inches. Emissivity can be taken as 0.8. σ = 5.6669 x 10^-8.

I know you need to find (q/L)rad and (q/L)convection but I'm having trouble figuring out h, the convection coefficient. can anyone help?

berkeman
Mentor
I have a heat transfer question, I work in a plant and am doing a re-insulation project. If an unexposed steel steam pipe (k=47) of diameter 10 inches, maintains an internal temperature of 460F and is exposed to ambient air (70F) flowing at 5 mph across the pipe. Determine the heat loss per unit length. The inside diameter of the pipe is 9.224 inches and the O.D. is 10.75 inches. Emissivity can be taken as 0.8. σ = 5.6669 x 10^-8.

I know you need to find (q/L)rad and (q/L)convection but I'm having trouble figuring out h, the convection coefficient. can anyone help?

For working in a plant and doing a project, that sure sounds like the wording of a schoolwork question...

For working in a plant and doing a project, that sure sounds like the wording of a schoolwork question...

haha wish it was. Finally figured it out, after reading my heat transfer book from a few years ago (thank you very much ), you just have to find the reynolds number and use that to find the Nusselt's number which gives you h.

berkeman
Mentor
Glad you figured it out. Q_Goest is the guy to thank in this case.