This information is part of the Modelica Standard Library maintained by the Modelica Association.
Calculation of the mean convective heat transfer coefficient kc for the air-side 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
- According to the kind of fin geometry the calculation is valid in a range of Re from 300 to 8000.
- medium = air
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
| 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 [-],|
The mean Nusselt number Nu representing the mean convective heat transfer coefficient kc is shown below for different fin geometries at similar dimensions.
- C.-C. Wang, C.-T. Chang:
- Heat and mass transfer for plate fin-and-tube heat exchangers, with and without hydrophilic coating.
In International Journal of Heat and Mass Transfer, volume 41, pages 3109-3120, 1998.
- C.-C. Wang, C.-J. Lee, C.-T. Chang, S.-P. Lina:
- Heat transfer and friction correlation for compact louvered fin-and-tube heat exchangers.
In International Journal of Heat and Mass Transfer, volume 42, pages 1945-1956, 1999.
- C.-C. Wang, W.-H. Tao, C.-J. Chang:
- An investigation of the airside performance of the slit fin-and-tube heat exchangers.
In International Journal of Refrigeration, volume 22, pages 595-603, 1999.
- C.-C. Wang, W.-L. Fu, C.-T. Chang:
- Heat Transfer and Friction Characteristics of Typical Wavy Fin-and-Tube Heat Exchangers.
In Experimental Thermal and Fluid Science, volume 14, pages 174-186, 1997.