12. Local and Average Heat Transfer Coefficients

\[\boxed{h = \frac{1}{L}\int_0^L h_x dx}\]





  • Friction factor and the heat transfer coefficient remain constant in fully developed laminar or turbulent flow, since the velocity and normalized temperature profiles do not vary in the flow direction.

  • Laminar and turbulent boundary layers have different heat transfer characteristics turbulent mixing typically increases heat transfer.