Help in Beam Width and Direction using DO radiation model

subham998 · November 4, 2019, 06:20

Dear All,

I have to define a cylindrical radiation beam in the DO radiation model in Ansys Fluent. Can someone guide me on how to choose a relevant beam width and height in order to set the profile? Also, is it possible to write a UDF that would allow only certain faces of a wall to behave as semitransparent and the remaining as opaque?

Thanks

LuckyTran · November 6, 2019, 15:34

Beam height??

Beam width is a solid angle in steradians. If your beam is cylindrical, the beam width is technically 0 (but you should input a very small number, which is the default anyway). So you actually don't have to provide anything here.

You do, need to give the beam direction, if applicable. If it's normal to the boundary then it's trivial.

Don't just straight to the most complicated UDF for all your needs. You can just split the boundary. Or even profile a heat flux profile and set the heat flux to 0 for the the opaque portions.

subham998 · November 10, 2019, 02:19

Thanks a lot for helping me out. I was able to solve the issue

Mr valz · August 30, 2022, 09:54

Hello,

Please I'm working on specie transport and trying to consider radiaition effect of the fire using discrete ordinate radiation model. Please what are the best BC to apply? also whats beam direction and what is best to set it as?

thanks.

November 4, 2019, 06:20	Help in Beam Width and Direction using DO radiation model	#1
subham998 New Member Subham Join Date: Sep 2018 Posts: 11 Rep Power: 7	Dear All, I have to define a cylindrical radiation beam in the DO radiation model in Ansys Fluent. Can someone guide me on how to choose a relevant beam width and height in order to set the profile? Also, is it possible to write a UDF that would allow only certain faces of a wall to behave as semitransparent and the remaining as opaque? Thanks

November 6, 2019, 15:34		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,704 Rep Power: 66	Beam height?? Beam width is a solid angle in steradians. If your beam is cylindrical, the beam width is technically 0 (but you should input a very small number, which is the default anyway). So you actually don't have to provide anything here. You do, need to give the beam direction, if applicable. If it's normal to the boundary then it's trivial. Don't just straight to the most complicated UDF for all your needs. You can just split the boundary. Or even profile a heat flux profile and set the heat flux to 0 for the the opaque portions. subham998 likes this.

August 30, 2022, 09:54	DO radiation Modelling	#4
Mr valz New Member Valentine Join Date: Aug 2022 Posts: 1 Rep Power: 0	Hello, Please I'm working on specie transport and trying to consider radiaition effect of the fire using discrete ordinate radiation model. Please what are the best BC to apply? also whats beam direction and what is best to set it as? thanks.

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November 10, 2019, 02:19		#3
subham998 New Member Subham Join Date: Sep 2018 Posts: 11 Rep Power: 7	Thanks a lot for helping me out. I was able to solve the issue