chtMultiRegionTwoPhaseEulerFoam mixed bc's.

ryaron · July 7, 2021, 09:37

hello, how do i enter a Robin's boundary condition between fluid and solid regions of the form:
k\nabla T=h(T-Tinf)+q
Tinf is initial temperature which equals ambient temperature.

where q is a fixed heat flux.
i am referring to the solver in the title only.
thx in advance

jmt · July 7, 2021, 10:57

Hello,

The stock boundary conditions for the OF CHT solver are implemented as Robin boundary conditions in software.

That is, the code for turbulentTemperatureCoupledBaffleMixed inherits from a mixed BC or the combination of a value and its derivative at the interface.

Notice that in the code (here), the gradient portion of this BC is set to zero (this->refGrad() = 0).

This leaves just a weighted average of the wall-adjacent cell-center temperatures to calculate the interface temperature. The average is weighted by the thermal conductivities of the neighboring reigons.

I hope this gives you a starting point for modifying the code to use Robin BCs.

jmt · July 7, 2021, 11:00

OH and I see that OpenFOAM already provides this convective BC. See here:

https://cpp.openfoam.org/v8/external...8H_source.html

July 7, 2021, 09:37	chtMultiRegionTwoPhaseEulerFoam mixed bc's.	#1
ryaron New Member Yaron Rosenstein Join Date: Apr 2013 Location: Israel Posts: 2 Blog Entries: 1 Rep Power: 0	hello, how do i enter a Robin's boundary condition between fluid and solid regions of the form: k\nabla T=h(T-Tinf)+q Tinf is initial temperature which equals ambient temperature. where q is a fixed heat flux. i am referring to the solver in the title only. thx in advance __________________ My website: https://sites.google.com/site/rosensteincfd/

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July 7, 2021, 10:57		#2
jmt Member Julian Join Date: Sep 2019 Posts: 33 Rep Power: 8	Hello, The stock boundary conditions for the OF CHT solver are implemented as Robin boundary conditions in software. That is, the code for turbulentTemperatureCoupledBaffleMixed inherits from a mixed BC or the combination of a value and its derivative at the interface. Notice that in the code (here), the gradient portion of this BC is set to zero (this->refGrad() = 0). This leaves just a weighted average of the wall-adjacent cell-center temperatures to calculate the interface temperature. The average is weighted by the thermal conductivities of the neighboring reigons. I hope this gives you a starting point for modifying the code to use Robin BCs.

July 7, 2021, 11:00		#3
jmt Member Julian Join Date: Sep 2019 Posts: 33 Rep Power: 8	OH and I see that OpenFOAM already provides this convective BC. See here: https://cpp.openfoam.org/v8/external...8H_source.html