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Natural Heat Transfer Check

Accessory component to check the heat transfer coefficient of Natural convection

 

Description

Equations

Variables

Connections

Parameters

Initial Conditions

See Also

Description

The Natural Heat Transfer Check component models the heat transfer coefficient calculation of Natural convection.

Before using HeatConvection component, you can check how to calculate the heat transfer coefficient internally.

Equations

Average temperature is :

T=Tin1Tin22

 

Heat transfer coefficient of Natural convection is calculated with :

h=`HeatTransfer.Properties.Fluid.AirNaturalHeatTransferpin, Tin1,Tin2,9.81,X,C__lam,n__lam,C__tur,n__tur,Threshold

( h=NukX )

( Nu={C__lamRan__lamRaThresholdC__turRan__turotherwise__)

( Ra=GrPr )

( Gr and Pr and k is calculated from pin and T )

 

Output is :

out=h

 

For details about the calculation of Fluid properties, see Fluid Properties Check.

Variables

Symbol

Units

Description

Modelica ID

T__

K

Averaged temperature between Tin[1] and Tin[2]

 

h

Wm2K

Heat transfer coefficient

 

Nu

Nusselt number

 

Pr

Prandtl number

 

Gr

Grashof number

 

Ra

Rayleigh number

 

k

WmK

Thermal conductivity

 

 

Connections

Name

Units

Condition

Description

Modelica ID

pin

Pa

-

Pressure input

pin

Tin2

K

-

Temperature inputs

Tin[2]

out

WmK

-

Heat transfer coefficient of Natural convection

out

Parameters

Symbol

Default

Units

Description

Modelica ID

X

0.1

m

Streamwise length

X

Clam

0.59

Gain parameter for Reynolds number in the generalized experimental equation of Natural convection generalized equation when Fluid is laminar.

C_lam

nlam

14

Exponent parameter for Reynolds number in the generalized experimental equation of Natural convection generalized equation when Fluid is laminar.

n_lam

Ctur

0.1

Gain parameter for Reynolds number in the generalized experimental equation of Natural convection generalized equation when Fluid is Turbulent.

C_tur

ntur

13

Exponent parameter for Reynolds number in the generalized experimental equation of Natural convection generalized equation when Fluid is Turbulent.

n_tur

Threshold

109

Threshold value for Reynolds number to define Laminar or Turbulent.

TH

Initial Conditions

Symbol

Units

Description

Modelica ID

T__0 

K

Initial condition of the averaged temperature

T(0)

See Also

Heat Transfer Library Overview

Properties Overview