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FC_plate_horizontal2_ND

 

 

The procedure FC_plate_horizontal2_ND(Ra, Pr: Nusselt) returns the Nusselt number for a heated horizontal downward facing flat plate or a cooled upward 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_horizontal2_ND is based on a compilation of correlations listed in Handbook of Heat Transfer, Third Ed. on pages 4.8-4.19 as reported in sectin 6.2.2 of Nellis and Klein. The correlation assumes laminar flow and is valid from 1000<Ra<1e10.

 

Example:

Ra=1.5e6

Pr=0.7

Call fc_plate_horizontal2_nd(Ra, Pr: Nusselt)

 

{Solution: 

Nusselt=8.061} 

 

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