[CFD_USER5454]

Hello everyone,
I have been working on a conjugate heat transfer problem where we are trying to observe how would the temperature of soil change when a fluid (gas) at different temperature passes through it. As far as I know in ansys fluent the closest approach is modelling soil as porous zone and since we are interested in temperature change in soil domain we need the non-equilibrium thermal model. Using this model we need to provide software with "Heat Transfer Coefficient" (located under interfacial area density tab). Does anyone know what are the ways to calculate the value for this coefficient? I have read some papers on heat transfer in packed beds suggesting some formulas (e.g. Furnas equation for spherical particles) that are derived by interpreting experimental data, but I was not convinced if those formulas would be suitable for our model.
the model: we have a pipe burried under soil, the pipe has some holes on it so the air passing through the pipe can penetrate into the surrounding soil (porous) domain. And we want to track the temperature change in the soil.
I would appreciate your comments.
Thanks