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particle/particle Conductive heat transfer in thermal engine

Asked by Rioual

Hello,

I am checking the implementation of particle/particle conductive heat transfer in thermal engine as presented in (1).
I do not understand the origin of the formula (9) in the framework:

Phi_ij = 2rc²(ki+kj)/d (Tj - Ti) (9) [ rc: contact radius ; k: thermal conductivity ; d:distance between particles less overlap ]

with the reference of Norouzi et al (2) precised in the article.

Norouzi (2) introduces (p.309) two different expressions for

* collisional contact conductive heat transfer
complex expression involving square root of contact time and square of contact radius....

 and

* static contact conductive heat transfer (p. 310)

Phi_ij = 4rc(1/ki+1/kj) (Tj - Ti)

which corresponds to the classical expression used elsewhere to describe particle conductive heat transfer
as in ligghts (https://www.cfdem.com/media/DEM/docu/fix_heat_gran_conduction.html).

Could you give me more infos about the approach considered in thermal engine (formula 9) ????

Thanks for all,

Best,

F.

(1)
https://www.researchgate.net/publication/335272631_An_open_framework_for_the_simulation_of_coupled_Thermo-Hydro-Mechanical_processes_in_Discrete_Element_Systems

(2) Norouzi, H. R., Zarghami, R., Sotudeh-Gharebagh, R., and Mostou
, N. (2016). Coupled CFD-DEM Modeling. Wiley.

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Robert Caulk (rcaulk) said : 		#1

Hello,

That is the thermal resistance using a cross sectional area based on the contact area between two spherical particles using the Kern method.

If you prefer, you can use the hertz method with

thermal.useKernMethod = False
thermal.useHertzMethod = True

Or set them both false to consider a wall consuming the space between the particle centers (better for continuum modeling).

You can easily add in which ever relationship you want there, such as the method you refer to in CFD.

Cheers,

robert

Revision history for this message
Rioual (francois-rioual-v) said : 		#2

Hello Robert,

Thanks for your input.
Do you have references concerning the Kern method and Hertz method ?

Thanks,

Fr.

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François Rioual

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----- Mail original -----
De: "Robert Caulk" <email address hidden>
À: "Rioual François" <email address hidden>
Envoyé: Lundi 11 Juillet 2022 11:06:01
Objet: Re: [Question #702421]: particle/particle Conductive heat transfer in thermal engine

Your question #702421 on Yade changed:
https://answers.launchpad.net/yade/+question/702421

    Status: Open => Answered

Robert Caulk proposed the following answer:
Hello,

That is the thermal resistance using a cross sectional area based on the
contact area between two spherical particles using the Kern method.

If you prefer, you can use the hertz method with

thermal.useKernMethod = False
thermal.useHertzMethod = True

Or set them both false to consider a wall consuming the space between
the particle centers (better for continuum modeling).

You can easily add in which ever relationship you want there, such as
the method you refer to in CFD.

Cheers,

robert

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Revision history for this message
Robert Caulk (rcaulk) said : 		#3

Hello Rioual,

I think probably your best bet for learning about Hertz and Kern methods is scholar.google.com.

Cheers,

Robert

Revision history for this message
Robert Caulk (rcaulk) said : 		#4

Marking question as "solved" since user question was directly answered.