modelPartialDuctHeatTransfer

partial model for rectangular duct heat transfer models

Extends from PartialFlowHeatTransfer.

Information

This model calculates the convective heat transfer coefficient α using the nusselt number correlation for rectangular air ducts by Muzychka and Yovanovich [1] (see function NusseltNumberMuzychka).

The air density, dynamic viscosity, thermal conductivity and Prandtl number are calculated as state variables. The Reynolds number is calculated using the density, dynmaic viscosity, flow velocity and the duct's cross section as characteristic length. The cross section is calculated using the duct's height and width.

The convective heat transfer coefficient is calculated as follows.

α = (Nu λ ) ⁄ √A_{cross-section}

References

[1]: Muzychka, Y. S.; Yovanovich, M. M. : Laminar Forced Convection Heat Transfer in the Combined Entry Region of Non-Circular Ducts ; Transactions of the ASME; Vol. 126; February 2004

Parameters

Type	Name	Description
Integer	nWidth	number of parallel segments in width direction
Modelica.Units.SI.Length	heights	height of duct
Modelica.Units.SI.Length	widths	width of duct
Boolean	uniWalTem	true if uniform wall temperature boundary conditions
Boolean	local	true if local nusslet number or false if average shall be calculated
Boolean	recDuct	true if rectangular duct is used for Sherwood number calculation, else flat gap is used.

Components

Type	Name	Description
Real	aspRats	aspect ratio between duct height and width
Modelica.Units.SI.CoefficientOfHeatTransfer	hCons
Modelica.Units.SI.ThermalConductivity	lambdas	thermal conductivity of medium
Modelica.Units.SI.Density	rhos	density of medium
Modelica.Units.SI.DynamicViscosity	mus	dynamic viscosity of medium
Real	Prs	Prandtl number
Real	Res	Reynolds number
Real	Nus	Nusselt number
Modelica.Units.SI.Area	croSecs	cross section of duct
Real	zSterns	dimensionless length

Revisions

August 21, 2018, by Martin Kremer:
First implementation.