This workbook implements standard, mostly empirical, correlations for forced convection over a heated, horizontal flat plate. It calculates for both laminar and turbulent flows and the transition from one to the other. It also covers cases involving an unheated starting length as seen in the second plot below.
Boundary layer thickness (solid lines) and convection coefficients (short-dashed) computed for laminar and turbulent boundary layers as well as for a “mixed” condition (long-dashed) in which the transition to turbulence occurs abruptly halfway down the flat plate.
Local Nusselt number for laminar boundary layer starting at the leading edge (red) and for a turbulent boundary layer assumed to have grown from the leading edge (blue). The Nusselt numbers computed using an integral boundary layer model for an unheated starting length are also plotted. Recall that Nux = h x/k, so that even though the Nusselt number is increasing with x/L, the convective heat transfer coefficient (the bottom line) is decreasing as the boundary layer grows in thickness.
The calculations included in this Excel workbook are all based on widely used empirical and semi-analytical forced convection correlations. The HTTflatp.exe module is an actual simulation of these same conditions. That module takes some of the “magic” out of the usual correlations in that one can actually “see” and interact with the underlying physics.
