viewFactor radiation model

jnagy · August 1, 2022, 07:51

Hi all!

I am running the externalSolarLoad tutorial in OpenFOAM-v2112/tutorials/heatTransfer/chtMultiRegionFoam/externalSolarLoad and what I am wondering about is,that qr is negative on the top of the cube (air_to_solid). What does that mean?

This seems to happen on faces, where the viewFactorField during initialization gets a value of 0, so no other surface can see it. What is the physical meaning of qr being negative on those surfaces?

Any input helps.

Thank you!

dlahaye · August 1, 2022, 08:29

Flux either inwards or outwards of the computational domain?

jnagy · August 2, 2022, 02:00

Dear Domenico,

thank you for your answer. Well the flux seems to be from the surface into the domain (see png attached). The sun is shining at a tilted angle from above, so I do not understand, why on this surface heat is lost from the wall to the air. Just because the other walls cannot "view" it according to the viewFactor?

dlahaye · August 2, 2022, 13:39

Not sure.

Switch to P1 or fvDOM radiation model? Switch to other tutorial?

August 1, 2022, 07:51	viewFactor radiation model	#1
jnagy New Member Jozsef Nagy Join Date: Dec 2018 Posts: 14 Rep Power: 7	Hi all! I am running the externalSolarLoad tutorial in OpenFOAM-v2112/tutorials/heatTransfer/chtMultiRegionFoam/externalSolarLoad and what I am wondering about is,that qr is negative on the top of the cube (air_to_solid). What does that mean? This seems to happen on faces, where the viewFactorField during initialization gets a value of 0, so no other surface can see it. What is the physical meaning of qr being negative on those surfaces? Any input helps. Thank you!

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August 1, 2022, 08:29		#2
dlahaye Senior Member Domenico Lahaye Join Date: Dec 2013 Posts: 729 Blog Entries: 1 Rep Power: 17	Flux either inwards or outwards of the computational domain?

August 2, 2022, 13:39		#4
dlahaye Senior Member Domenico Lahaye Join Date: Dec 2013 Posts: 729 Blog Entries: 1 Rep Power: 17	Not sure. Switch to P1 or fvDOM radiation model? Switch to other tutorial?