Convection Coefficients

A reference for some typical convection coefficients.

Approximate Values of Convection Coefficients

Flow Type W/(m2⋅K)
Forced convection – low speed flow of air over a surface 10
Forced convection – moderate speed flow of air over a surface 100
Forced convection – moderate speed cross-flow of air over a cylinder 200
Forced convection – moderate flow of water in a pipe 3000
Forced convection – molten metals flowing in tubes 2000 to 45000
Forced convection – oil flowing in tubes 300 to 1700
Forced convection – boiling water in a pipe 50000
Gases in free convection 5 to 37
Water in free convection 100 to 1200
Oil in free convection 50 to 350