Modeling of particle absorption in air filter in CFX

j-avdeev · August 20, 2012, 03:59

Hello.

I am trying to setup absorption efficiency of air filter. I have particles of different size and want setup, that air filter pass for example 1% of big particles, 2% of medium particles and 3% of small particles (filter retains 99% of big, 98% of medium and 97% of small particles).

I can find corresponding options (almost) for this case - in "wall" object, but can't find this in "interface" object and in porous media.

Is it possible to reach my goal with using interface? Or I have to use something like "user defined functions"? Or maybe it is possible with walls (I need that particles pass through surface)?

Thank you.

ghorrocks · August 20, 2012, 06:01

If you are doing this with Lagrangian particle tracking you will need a fortran sub routine to do this. If you are doing this with a Eularian model it can be done with a source term (I think).

j-avdeev · August 20, 2012, 06:27

ghorrocks, thank for your rapid answer.

Also can you tell - is it possible to solve this problem with using CFX Expression Language (CEL) or fortran only?

And if it will on fortran - can you show something for example? Or give a link, where I can find something close to my case.

ghorrocks · August 20, 2012, 06:46

If you are doing a Eularian this might be able to be done by a CEL expression.

But for Lagrangian particle tracking you will need fortran. I do not have an example to hand, but the documentation includes some examples of fortran for particle tracking. I think it is in the CFX-Pre manual.

j-avdeev · August 20, 2012, 07:37

Thank you, Glenn.

Also can you tell - where can I insert fortran code for interface? For wall - exist separate window, but I can not find same for interface.

Felggv · August 20, 2012, 10:40

j-avdeev,

It's kinda tricky to link FORTRAN routines with CFX. Many people had asked about it before, you can search for it later!

Revise the concept of what you're trying to do. CEL supports if statements besides another basic things (look at the manual) it's very useful and maybe you won't even need to use FORTRAN.

Good luck

_srs_ · October 28, 2015, 10:19

Hello j-avdeev,

did you find a solution for your problem?

I want to simulate the absorption of dust in a filter. The filter itself is set up as porous medium. I have air as continous fluid an use the Lagrangian particle tracking.

Did you use fortran or is there any other way to simulate the accumulation of dust especially in a porous medium?

Thank you

j-avdeev · October 31, 2015, 07:25

Hello, _srs_
It was too difficult for me to make through routines.
So I solve it in 2 steps:
1. Made simulation of the porous medium without dust - the purpose of the calculation to estimate the average length of the passage of dust particles inside the material.
2. Further, was analytically calculated number of particles of a given diameter that can pass a given length, of the probability of the particle retention in the material.

_srs_ · November 2, 2015, 06:29

Thanks a lot for your answer j-avdeev

I have some more questions about your solution.

Step 1:
How did you simulate the averrage passage of dust particles in the material without dust?

Step 2:
Did you simulate the particle retention in the porous medium in a final step (if yes: how? I did´t find a way to model the particle absorption)

August 20, 2012, 03:59	Modeling of particle absorption in air filter in CFX	#1
j-avdeev Member Avdeev Evgeniy Join Date: Jan 2011 Location: Togliatty, Russia Posts: 69 Blog Entries: 1 Rep Power: 21	Hello. I am trying to setup absorption efficiency of air filter. I have particles of different size and want setup, that air filter pass for example 1% of big particles, 2% of medium particles and 3% of small particles (filter retains 99% of big, 98% of medium and 97% of small particles). I can find corresponding options (almost) for this case - in "wall" object, but can't find this in "interface" object and in porous media. Is it possible to reach my goal with using interface? Or I have to use something like "user defined functions"? Or maybe it is possible with walls (I need that particles pass through surface)? Thank you.

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August 20, 2012, 06:01		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	If you are doing this with Lagrangian particle tracking you will need a fortran sub routine to do this. If you are doing this with a Eularian model it can be done with a source term (I think).

August 20, 2012, 06:27		#3
j-avdeev Member Avdeev Evgeniy Join Date: Jan 2011 Location: Togliatty, Russia Posts: 69 Blog Entries: 1 Rep Power: 21	ghorrocks, thank for your rapid answer. Also can you tell - is it possible to solve this problem with using CFX Expression Language (CEL) or fortran only? And if it will on fortran - can you show something for example? Or give a link, where I can find something close to my case.

August 20, 2012, 06:46		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	If you are doing a Eularian this might be able to be done by a CEL expression. But for Lagrangian particle tracking you will need fortran. I do not have an example to hand, but the documentation includes some examples of fortran for particle tracking. I think it is in the CFX-Pre manual.

August 20, 2012, 07:37		#5
j-avdeev Member Avdeev Evgeniy Join Date: Jan 2011 Location: Togliatty, Russia Posts: 69 Blog Entries: 1 Rep Power: 21	Thank you, Glenn. Also can you tell - where can I insert fortran code for interface? For wall - exist separate window, but I can not find same for interface.

August 20, 2012, 10:40		#6
Felggv Member Felipe Gobbi Join Date: Apr 2012 Location: Brazil Posts: 76 Rep Power: 14	j-avdeev, It's kinda tricky to link FORTRAN routines with CFX. Many people had asked about it before, you can search for it later! Revise the concept of what you're trying to do. CEL supports if statements besides another basic things (look at the manual) it's very useful and maybe you won't even need to use FORTRAN. Good luck

October 28, 2015, 10:19		#7
_srs_ New Member Join Date: Oct 2015 Posts: 4 Rep Power: 10	Hello j-avdeev, did you find a solution for your problem? I want to simulate the absorption of dust in a filter. The filter itself is set up as porous medium. I have air as continous fluid an use the Lagrangian particle tracking. Did you use fortran or is there any other way to simulate the accumulation of dust especially in a porous medium? Thank you

October 31, 2015, 07:25		#8
j-avdeev Member Avdeev Evgeniy Join Date: Jan 2011 Location: Togliatty, Russia Posts: 69 Blog Entries: 1 Rep Power: 21	Hello, _srs_ It was too difficult for me to make through routines. So I solve it in 2 steps: 1. Made simulation of the porous medium without dust - the purpose of the calculation to estimate the average length of the passage of dust particles inside the material. 2. Further, was analytically calculated number of particles of a given diameter that can pass a given length, of the probability of the particle retention in the material.

November 2, 2015, 06:29		#9
_srs_ New Member Join Date: Oct 2015 Posts: 4 Rep Power: 10	Thanks a lot for your answer j-avdeev I have some more questions about your solution. Step 1: How did you simulate the averrage passage of dust particles in the material without dust? Step 2: Did you simulate the particle retention in the porous medium in a final step (if yes: how? I did´t find a way to model the particle absorption)