Heat Transfer Coefficients — Internal Forced Convection
Isothermal Tube
Figure 4-39: Schematic representation of geometry and parameters for the averaged heat transfer coefficient correlation applied to forced convection in an isothermal circular tube.
This correlation corresponds to equations 8.55 and 8.61 in Ref. 21:
(4-189)
where Pr = μCp ⁄ k, and ReD = ρUextD ⁄ μ. D (the tube diameter) and the velocity U are correlation inputs. All material data are evaluated at (T + Text) ⁄ 2 except μs, which is evaluated at the wall temperature, T. The laminar-turbulent transition at ReD = 2500 is handled by the use of a smoothed Heaviside function with a transition of size 250, which corresponds to 10% of the threshold value.