DPM Particles injection

mtalha976 · December 10, 2020, 05:32

Hi ,

I have a problem simulating particles in 2D. I have a simple geometry surface where this is air inlet and air outlet . There is a Rectangle surface which is used to inject the particles. When run the calculation it says Zone not slit and the particles are not injected. I don't know what is the problem. Only air flow contours are made . Kindly Help me through this I am stuck.

Thanks.

Regards,

Muhammad Talha

pakk · December 10, 2020, 06:11

Do you get the same warning if you don't use particles?

mtalha976 · December 10, 2020, 06:33

yes it stays the same.

pakk · December 10, 2020, 06:38

Then that warning has nothing to do with your particles.

Second question: are you 100% sure that your initial particle locations are inside your domain? (do you use injection files?) be careful if they are at the boundary of the domain, fluent might place them just outside, and ignore them.

mtalha976 · December 10, 2020, 06:44

yes its inside the domain . There is rectangular surface which is at the middle of the surface geometry, which is Boolean subtracted. from That surface I am injecting the particles. I did not used UDF Injection Files. I gave a velocity , mass flow rate and diameter.

pakk · December 10, 2020, 06:52

You say that the particles were not injected.
What exactly did you do to come to that conclusion?

mtalha976 · December 11, 2020, 10:09

I mean to say that the I can not see the particles injected through the rectangular surface.

DnyanMiri · December 12, 2020, 01:56

What injection method did you use to inject particles in the domain? Why not try surface injection at first and see if there is a problem or not.
Also, Does your setup work if the DPM is not enabled?

mtalha976 · December 12, 2020, 04:57

Hi,
I have used DPM method, I tried Surface injection , The problem is still there. It works when only air is flowing through inlet and going to outlet.

pakk · December 12, 2020, 06:07

What do you get in the TUI when you (try to) release particles?

(and just to be sure: have you ever successfully released particles in a different fluent simulation?

mtalha976 · December 12, 2020, 06:48

The console says 0 particles tracked in 2D. I have tried with 3-D case with a circle injecting on one face of the cube. That works fine. I can see the particles there.

pakk · December 12, 2020, 10:18

Can you just copy the literal text that shows up?

mtalha976 · December 12, 2020, 12:49

Hi look at this , I have attached the pic.

pakk · December 12, 2020, 15:29

I see that 100 particles were injected. And you are plotting particle traces. So why again do you think it failed? Can you make a picture of something that failed?

mtalha976 · December 13, 2020, 05:48

The particles injected are incomplete. Moreover there is no fate information. The particles track is just air flowing through it.

pakk · December 13, 2020, 09:46

The paths are incomplete, which means that the calculation ended before particles reached an exit.

So no finished paths, no fates to be reported.

Clearly, your particles were released. They just stayed inside your domain until the end of the calculation, your image supports that.

So, everything worked as it should. You don't have a problem...

mtalha976 · December 13, 2020, 10:28

Thanks for the reply. ok it means i should further reduce the time step size and increase the number of steps.

and ONLY DPM model is sufficient for injecting aerosol particles? i have selected as inert particle of water liquid and fluid air in the material then i gave the injection velocity and inlet velocity and pressure outlet. Then hybrid Initialization.

will this be enough for this case? or i have to use VOF or Species transport?
Kindly guide me through it.

pakk · December 13, 2020, 10:36

Quote:

Originally Posted by mtalha976

Thanks for the reply. ok it means i should further reduce the time step size and increase the number of steps.

?

No, it does not mean that. Do you expect that particles will leave your domain if you simulate longer? Your picture does not really look like that... Why can't you accept that this is the final result? What is wrong with it???

If anything, only increase number of steps. Don't reduce the time step further, why would you....

mtalha976 · December 13, 2020, 10:43

No i don't want to leave the domain. I just want to remain in the domain. I am confused which particles are these , i mean to say that i have air also coming and injecting water liquid through same inlet. So these tracks are of which one? have I given the air correct boundary condition?

mtalha976 · December 13, 2020, 10:44

and further ONLY DPM model is sufficient for injecting aerosol particles? i have selected as inert particle of water liquid and fluid air in the material then i gave the injection velocity and inlet velocity and pressure outlet. Then hybrid Initialization.

will this be enough for this case? or i have to use VOF or Species transport?

December 10, 2020, 05:32	DPM Particles injection	#1
mtalha976 Member Muhammad Talha Join Date: Feb 2020 Posts: 32 Rep Power: 6	Hi , I have a problem simulating particles in 2D. I have a simple geometry surface where this is air inlet and air outlet . There is a Rectangle surface which is used to inject the particles. When run the calculation it says Zone not slit and the particles are not injected. I don't know what is the problem. Only air flow contours are made . Kindly Help me through this I am stuck. Thanks. Regards, Muhammad Talha

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December 10, 2020, 06:11		#2
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 27	Do you get the same warning if you don't use particles?

December 10, 2020, 06:33		#3
mtalha976 Member Muhammad Talha Join Date: Feb 2020 Posts: 32 Rep Power: 6	yes it stays the same.

December 10, 2020, 06:38		#4
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 27	Then that warning has nothing to do with your particles. Second question: are you 100% sure that your initial particle locations are inside your domain? (do you use injection files?) be careful if they are at the boundary of the domain, fluent might place them just outside, and ignore them.

December 10, 2020, 06:44		#5
mtalha976 Member Muhammad Talha Join Date: Feb 2020 Posts: 32 Rep Power: 6	yes its inside the domain . There is rectangular surface which is at the middle of the surface geometry, which is Boolean subtracted. from That surface I am injecting the particles. I did not used UDF Injection Files. I gave a velocity , mass flow rate and diameter.

December 10, 2020, 06:52		#6
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 27	You say that the particles were not injected. What exactly did you do to come to that conclusion?

December 11, 2020, 10:09		#7
mtalha976 Member Muhammad Talha Join Date: Feb 2020 Posts: 32 Rep Power: 6	I mean to say that the I can not see the particles injected through the rectangular surface.

December 12, 2020, 01:56		#8
DnyanMiri Member Dnyanesh Mirikar Join Date: Jul 2019 Posts: 35 Rep Power: 7	What injection method did you use to inject particles in the domain? Why not try surface injection at first and see if there is a problem or not. Also, Does your setup work if the DPM is not enabled?

December 12, 2020, 04:57		#9
mtalha976 Member Muhammad Talha Join Date: Feb 2020 Posts: 32 Rep Power: 6	Hi, I have used DPM method, I tried Surface injection , The problem is still there. It works when only air is flowing through inlet and going to outlet.

December 12, 2020, 06:07		#10
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 27	What do you get in the TUI when you (try to) release particles? (and just to be sure: have you ever successfully released particles in a different fluent simulation?

December 12, 2020, 06:48		#11
mtalha976 Member Muhammad Talha Join Date: Feb 2020 Posts: 32 Rep Power: 6	The console says 0 particles tracked in 2D. I have tried with 3-D case with a circle injecting on one face of the cube. That works fine. I can see the particles there.

December 12, 2020, 10:18		#12
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 27	Can you just copy the literal text that shows up?

December 12, 2020, 15:29		#14
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 27	I see that 100 particles were injected. And you are plotting particle traces. So why again do you think it failed? Can you make a picture of something that failed?

December 13, 2020, 05:48		#15
mtalha976 Member Muhammad Talha Join Date: Feb 2020 Posts: 32 Rep Power: 6	The particles injected are incomplete. Moreover there is no fate information. The particles track is just air flowing through it.

December 13, 2020, 09:46		#16
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 27	The paths are incomplete, which means that the calculation ended before particles reached an exit. So no finished paths, no fates to be reported. Clearly, your particles were released. They just stayed inside your domain until the end of the calculation, your image supports that. So, everything worked as it should. You don't have a problem...

December 13, 2020, 10:28		#17
mtalha976 Member Muhammad Talha Join Date: Feb 2020 Posts: 32 Rep Power: 6	Thanks for the reply. ok it means i should further reduce the time step size and increase the number of steps. and ONLY DPM model is sufficient for injecting aerosol particles? i have selected as inert particle of water liquid and fluid air in the material then i gave the injection velocity and inlet velocity and pressure outlet. Then hybrid Initialization. will this be enough for this case? or i have to use VOF or Species transport? Kindly guide me through it.

December 13, 2020, 10:43		#19
mtalha976 Member Muhammad Talha Join Date: Feb 2020 Posts: 32 Rep Power: 6	No i don't want to leave the domain. I just want to remain in the domain. I am confused which particles are these , i mean to say that i have air also coming and injecting water liquid through same inlet. So these tracks are of which one? have I given the air correct boundary condition?

December 13, 2020, 10:44		#20
mtalha976 Member Muhammad Talha Join Date: Feb 2020 Posts: 32 Rep Power: 6	and further ONLY DPM model is sufficient for injecting aerosol particles? i have selected as inert particle of water liquid and fluid air in the material then i gave the injection velocity and inlet velocity and pressure outlet. Then hybrid Initialization. will this be enough for this case? or i have to use VOF or Species transport?