Contents - Index


FC_plate_horizontal1_ND

 

 

The procedure FC_plate_horizontal1_ND(Ra, Pr: Nusselt) returns the Nusselt number for a heated horizontal upward facing flat plate or a cooled downward facing flat plate given the Rayleigh and Prandtl numbers. The Rayleigh number should be calculated based on the length scale L* which is defined as the ratio of the surface area of the plate to its perimeter

 

Inputs:

Ra - Rayleigh number based on L* [-]

 

where 

Ra = g*L^3*beta*DT/(nu*alpha)

g = gravity

L* = plate area/perimeter

beta = volumetric thermal expansion coefficient

DT = magnitude of the temperature difference

nu = kinematic viscosity

alpha = thermal diffusivity

 

Pr - Prandtl number of fluid [-]

 

Outputs:

Nusselt - average Nusselt number based on plate length [-]

 

where 

Nusselt = h_bar*L*/k

h_bar = average heat transfer coefficient

k = conductivity

 

Notes:

The procedure FC_plate_horizontal1_ND is based on a compilation of correlations listed in Handbook of Heat Transfer, Third Ed. on pages 4.8-4.19 as described in section 6.2.2 of Nellis and Klein. These correlations include and weight the Nusselt number contributions from the laminar and turbulent boundary layers.

 

The correlation is valid from 1<Ra<1e10. 

 

Example:

Ra=1.5e6

Pr=0.7

Call FC_plate_horizontal1_ND(Ra, Pr: Nusselt)

 

{Solution: Nusselt=17.02} 

 

Free Convection Index