How to set effective thermal conductivity

highnelly · July 31, 2009, 05:00

Hi,

I am modelling heat transfer in porous medium with star-ccm+. Does anyone know how I set the effective thermal conductivity of the porous region?

Thanks for any help!!

vishyaroon · July 31, 2009, 10:58

Are you asking for this equation ( I got it directly from STAR CCM+ help menu)?

k_eff = k + mu_t*Cp/Pr_t

However one thing I have always had issue with using porous media with heat transfer in STAR CCM+ is that the equations do not account for the porosity and the solid energy, which play a significant role in transient problems.

highnelly · July 31, 2009, 11:10

No,

By effective thermal conductivity I mean a weighted thermal conductivity based on the porosity of the medium, i.e k_eff=k_a+(1-e)K_s. But I guess you have answered my question by saying that the solid is not accounted for.

What I am thinking of doing is forcing the thermal conductivity to the desired value in the porous medium region through some user coding. I see Star-CD have this option in the GUI so I think (hope) it will be in Star-CCM soon.

Thanks

vishyaroon · July 31, 2009, 11:18

My group has also been in search for this and hopefully CCM+ should come up with this option soon. I'm not sure if they have the option of user sub-routine in version 4.04. I remember we had once given a detailed request on this to adapco.

July 31, 2009, 05:00	How to set effective thermal conductivity	#1
highnelly New Member Join Date: Mar 2009 Posts: 18 Rep Power: 17	Hi, I am modelling heat transfer in porous medium with star-ccm+. Does anyone know how I set the effective thermal conductivity of the porous region? Thanks for any help!!

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July 31, 2009, 10:58		#2
vishyaroon Senior Member Aroon Join Date: Apr 2009 Location: Racine WI Posts: 148 Rep Power: 17	Are you asking for this equation ( I got it directly from STAR CCM+ help menu)? k_eff = k + mu_t*Cp/Pr_t However one thing I have always had issue with using porous media with heat transfer in STAR CCM+ is that the equations do not account for the porosity and the solid energy, which play a significant role in transient problems.

July 31, 2009, 11:10		#3
highnelly New Member Join Date: Mar 2009 Posts: 18 Rep Power: 17	No, By effective thermal conductivity I mean a weighted thermal conductivity based on the porosity of the medium, i.e k_eff=k_a+(1-e)K_s. But I guess you have answered my question by saying that the solid is not accounted for. What I am thinking of doing is forcing the thermal conductivity to the desired value in the porous medium region through some user coding. I see Star-CD have this option in the GUI so I think (hope) it will be in Star-CCM soon. Thanks

July 31, 2009, 11:18		#4
vishyaroon Senior Member Aroon Join Date: Apr 2009 Location: Racine WI Posts: 148 Rep Power: 17	My group has also been in search for this and hopefully CCM+ should come up with this option soon. I'm not sure if they have the option of user sub-routine in version 4.04. I remember we had once given a detailed request on this to adapco.