Information
This icon indicates classes containing only documentation, intended for general description of, e.g., concepts and features of a package.
Extends from Modelica.Icons.Information
(Icon for general information packages).
Package Contents
Information
Calculation of the mean convective heat transfer coefficient kc for the airside heat transfer of heat exchangers with flat tubes and several fin geometries.
Functions kc_flatTube and kc_flatTube_KC
There are basically three differences:

The function kc_flatTube is using kc_flatTube_KC but offers additional output variables like e.g. Reynolds number or Nusselt number and failure status (an output of 1 means that the function is not valid for the inputs).

Generally the function kc_flatTube_KC is numerically best used for the calculation of the mean convective heat transfer coefficient kc at known mass flow rate.

You can perform an inverse calculation from kc_flatTube_KC, where an unknown mass flow rate is calculated out of a given mean convective heat transfer coefficient kc
Restriction
 According to the kind of fin geometry the calculation is valid in a range of Re from 100 to 5000.
 medium = air
Geometry
Calculation
The mean convective heat transfer coefficient kc for heat exchanger is calculated through the corresponding Coulburn factor j :
j = f(geometry, Re)
with the resulting mean convective heat transfer coefficient kc
kc = j * Re_L_p * Pr^(1/3) * lambda / L_p (Louver fin)
or
kc = j * Re_D_h * Pr^(1/3) * lambda / D_h (Rectangular offset strip fin)
with
D_h  as hydraulic diameter [m], 
kc  as mean convective heat transfer coefficient [W/(m2K)], 
lambda  as heat conductivity of fluid [W/(mK)], 
L_p  as louver pitch [m], 
Nu_D_h = kc*D_h/lambda  as mean Nusselt number based on hydraulic diameter [], 
Nu_L_p = kc*L_p/lambda  as mean Nusselt number based on louver pitch [], 
Pr = eta*cp/lambda  as Prandtl number [], 
Re_D_h = rho*v*D_h/eta  as Reynolds number based on hydraulic diameter [], 
Re_L_p = rho*v*L_p/eta  as Reynolds number based on louver pitch [], 
Verification
The mean Nusselt number Nu representing the mean convective heat transfer coefficient kc is shown below for different fin geometries at similar dimensions.
References
 Y.J. CHANG and C.C. WANG:
 A generalized heat transfer correlation for louver fin geometry.
In International Journal of Heat and Mass Transfer, volume 40, No. 3, pages 533544, 1997.
 Y.J. CHANG and C.C. WANG:
 Air Side Performance of Brazed Aluminium Heat Exchangers.
In Journal of Enhanced Heat Transfer, volume 3, No. 1, pages 1528, 1996.
 R.M. Manglik, A.E. Bergles:
 Heat Transfer and Pressure Drop Correlations for the Rectangular Offset Strip Fin Compact Heat Exchanger.
In Experimental Thermal and Fluid Science, volume 10, pages 171180, 1995.
Extends from Modelica.Icons.Information
(Icon for general information packages).
Information
Calculation of the mean convective heat transfer coefficient kc for the airside heat transfer of heat exchangers with round tubes and several fin geometries.
Functions kc_roundTube and kc_roundTube_KC
There are basically three differences:

The function kc_roundTube is using kc_roundTube_KC but offers additional output variables like e.g. Reynolds number or Nusselt number and failure status (an output of 1 means that the function is not valid for the inputs).

Generally the function kc_roundTube_KC is numerically best used for the calculation of the mean convective heat transfer coefficient kc at known mass flow rate.

You can perform an inverse calculation from kc_roundTube_KC, where an unknown mass flow rate is calculated out of a given mean convective heat transfer coefficient kc
Restriction
 According to the kind of fin geometry the calculation is valid in a range of Re from 300 to 8000.
 medium = air
Geometry
Calculation
The mean convective heat transfer coefficient kc for heat exchanger is calculated through the corresponding Coulburn factor j :
j = f(geometry, Re)
with the resulting mean convective heat transfer coefficient kc
kc = j * Re * Pr^(1/3) * lambda / D_c
with
D_c  as fin collar diameter [m], 
kc  as mean convective heat transfer coefficient [W/(m2K)], 
lambda  as heat conductivity of fluid [W/(mK)], 
Nu = kc*D_c/lambda  as mean Nusselt number [], 
Pr = eta*cp/lambda  as Prandtl number [], 
Re = rho*v*D_c/eta  as Reynolds number [], 
Verification
The mean Nusselt number Nu representing the mean convective heat transfer coefficient kc is shown below for different fin geometries at similar dimensions.
References
 C.C. Wang, C.T. Chang:
 Heat and mass transfer for plate finandtube heat exchangers, with and without hydrophilic coating.
In International Journal of Heat and Mass Transfer, volume 41, pages 31093120, 1998.
 C.C. Wang, C.J. Lee, C.T. Chang, S.P. Lina:
 Heat transfer and friction correlation for compact louvered finandtube heat exchangers.
In International Journal of Heat and Mass Transfer, volume 42, pages 19451956, 1999.
 C.C. Wang, W.H. Tao, C.J. Chang:
 An investigation of the airside performance of the slit finandtube heat exchangers.
In International Journal of Refrigeration, volume 22, pages 595603, 1999.
 C.C. Wang, W.L. Fu, C.T. Chang:
 Heat Transfer and Friction Characteristics of Typical Wavy FinandTube Heat Exchangers.
In Experimental Thermal and Fluid Science, volume 14, pages 174186, 1997.
Extends from Modelica.Icons.Information
(Icon for general information packages).