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-   -   How can I apply "Beam width" and "Beam Direction"? (https://www.cfd-online.com/Forums/fluent/221803-how-can-i-apply-beam-width-beam-direction.html)

aja1345 October 30, 2019 19:05
How can I apply "Beam width" and "Beam Direction"?
 
when the "semi-transparent" is selected in the BC type under the radiation tab of the wall, you need to set "beam width" and "beam direction". i have seen the relevant information in the HELP document, but i still do not understand their meanings and do not know how to set them. Is there anyone who can explain their meanings and help me? the attachment is a case that i need to set in this problem. please help me how to set these parameters. I want to apply beam directions throughout the following plate. How?



Thanks.


http://uupload.ir/files/hwde_yutu.png

crubio.abujas October 31, 2019 02:34
Hellol aja,


The beam width is how the program is numerically considering the width of the beam. Is expressed in spherical coordinates ranges (inclination and accimuth). This expresses a "square" in such coordinate system where fluent is performing the radiation calculation.
If you are not aware of which number to use therecomandation is to keep the values by default.


The beam direction is pretty much what it sounds. It represent the direction from which your radiation is applied. Generally from distant focal sources such as the sun it is considered to have a uniform direction. If your radiation source is not so distant and you want to consider this effect (as you shown in your sketch) you have to tell fluent how the dirección change with the position. You can do this using profiles, functions or UDF.



Hope it helps

LuckyTran October 31, 2019 10:20
Put the direction vector for the normal direction of the plate.


Unless I missed something, you should be able to input a negative solid angle for a diverging beam.

aja1345 October 31, 2019 12:31
Quote:
Originally Posted by crubio.abujas (Post 748529)
Hellol aja,


The beam width is how the program is numerically considering the width of the beam. Is expressed in spherical coordinates ranges (inclination and accimuth). This expresses a "square" in such coordinate system where fluent is performing the radiation calculation.
If you are not aware of which number to use therecomandation is to keep the values by default.


The beam direction is pretty much what it sounds. It represent the direction from which your radiation is applied. Generally from distant focal sources such as the sun it is considered to have a uniform direction. If your radiation source is not so distant and you want to consider this effect (as you shown in your sketch) you have to tell fluent how the dirección change with the position. You can do this using profiles, functions or UDF.



Hope it helps

Thanks. sun is considered in this work because the problem is about solar photovoltaic panels. But I have to apply heat flux(w/m2) on the out surface of panel(glass) because the case is 2D.

aja1345 October 31, 2019 12:35
Quote:
Originally Posted by LuckyTran (Post 748575)
Put the direction vector for the normal direction of the plate.


Unless I missed something, you should be able to input a negative solid angle for a diverging beam.



Model is as follows:


http://uupload.ir/files/3mvo_33333333.png


How can I apply direction vector?


I applied (1,-1,0) in direction vector. The case is 2D.

LuckyTran November 1, 2019 10:07
It's in the HELP documentation which you've already read and mastered.


The sun is definitely not a diverging source. I would definitely not put a negative solid angle. That was a terrible picture to provide. Next time, give something that makes sense.


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