[Robin.Kamenicky]

Dear Foamers,


I want to discuss the implementation of a spherical heat transfer model. Thus the calculation of heat transfer coefficient between sphere surface and fluid within the sphere for Eulerian multi-fluid approach. The code is in sphericalHeatTransfer.C for both ESI and Foundation versions.


The code is following:

60.0
  *max(pair_.dispersed(), residualAlpha_)
 *pair_.continuous().kappa()
 /sqr(pair_.dispersed().d());

which effectively means in pseudo-code

6*alpha_d/d *Nu_d*kappa_c/d

where the Nu is the Nusselt number equal to 10 and 6*alpha_d/d is the interfacial area concentration. alpha is volume fraction, kappa thermal conductivity, d is particle diameter, subscript c stands for continuous phase and subscript d for dispersed phase.


I would expect to use kappa_d instead of kappa_c because the model is used for heat transfer coefficient into dispersed phase (into the fluid within the sphere). What do you think?


Also, if somebody has the analytical solution for the heat transfer from a sphere surface into the fluid inside it, I would appreciate sharing it.


Have a good day,
Robin