shape factor

njundale · October 11, 2012, 00:49

hi guys,

can u tell me how to calculate shape/view factor in CFX.

Thanx in advance.

ghorrocks · October 11, 2012, 05:56

This is done internally when you do a radiation model. I do not know of a way to get it out in post processing - but I have never tried.

Possa · October 11, 2012, 09:34

Hello Nikhil,

If you mean radiation shape factor, as far as I know CFX does not use it for calculations it solves by ray tracing method calculating the radiation heat flux directly.
The Monte Carlo method can be used to calculate shape factors but it does not need to calculate them to solve the radiation problem. Indeed if you are using a participating media there is no sense in using radiation shape factors (save specific exceptions).

Regards,
Possa

ghorrocks · October 11, 2012, 18:28

Talita's comment is correct - CFX works out view factors internally from radiation surface facet to other radiation surface facets. It does not work it out based on bodies as manual analysis often does. This means shape factors does not exist per-se in the CFX implementation.

October 11, 2012, 00:49	shape factor	#1
njundale New Member nikhil Join Date: Aug 2011 Posts: 3 Rep Power: 14	hi guys, can u tell me how to calculate shape/view factor in CFX. Thanx in advance.

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October 11, 2012, 05:56		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	This is done internally when you do a radiation model. I do not know of a way to get it out in post processing - but I have never tried.

October 11, 2012, 09:34		#3
Possa New Member Talita Possamai Join Date: Sep 2012 Posts: 23 Rep Power: 13	Hello Nikhil, If you mean radiation shape factor, as far as I know CFX does not use it for calculations it solves by ray tracing method calculating the radiation heat flux directly. The Monte Carlo method can be used to calculate shape factors but it does not need to calculate them to solve the radiation problem. Indeed if you are using a participating media there is no sense in using radiation shape factors (save specific exceptions). Regards, Possa

October 11, 2012, 18:28		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	Talita's comment is correct - CFX works out view factors internally from radiation surface facet to other radiation surface facets. It does not work it out based on bodies as manual analysis often does. This means shape factors does not exist per-se in the CFX implementation.