Using DPM

PaulJones · October 19, 2022, 10:16

Hi,

I have a simpel case of air entering a vessel tangentially and leaving it at the top of it. This air is transporting particles with density 400x density of air. At the bottom there is an opening where the particles should leave the domain, but no air can leave here (mass flux 0).
I gave the particles mass and use gravity. I see that the particles keep rotating in the vessel for ever, without descending down by gravity. Does anyone have an idea whats going wrong here?
Thanks in advance.

alainislas · October 26, 2022, 08:32

what is your particle size? particle velocity? Do you have two way coupling enabled? Please post some images of your DPM setup and domain.

Klavoir · October 26, 2022, 09:38

Particle diameter 1cm, velocity 70 m/s, no two way coupling, shape factor 0.06

alainislas · October 26, 2022, 10:36

Ok, particles are very big and very very fast!. At such condtions I feel that most likely your particles adopt ballistic behavior.
1) Can you please calculate the Stokes number?
2) Also, calculate the particle settling velocity.
3) Please post images of your domain, or partilcle tracks

Klavoir · October 26, 2022, 10:48

Hi,

I will, but can Fluent calculate 1 and 2?

alainislas · October 26, 2022, 11:00

No, you need to estimate them ... These numbers will give you very important information of your system! Please read the theory

October 19, 2022, 10:16	Using DPM	#1
PaulJones New Member Utrecht Join Date: Oct 2022 Posts: 1 Rep Power: 0	Hi, I have a simpel case of air entering a vessel tangentially and leaving it at the top of it. This air is transporting particles with density 400x density of air. At the bottom there is an opening where the particles should leave the domain, but no air can leave here (mass flux 0). I gave the particles mass and use gravity. I see that the particles keep rotating in the vessel for ever, without descending down by gravity. Does anyone have an idea whats going wrong here? Thanks in advance.

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October 26, 2022, 08:32		#2
alainislas Senior Member Alain Islas Join Date: Nov 2019 Location: Mexico Posts: 142 Rep Power: 6	what is your particle size? particle velocity? Do you have two way coupling enabled? Please post some images of your DPM setup and domain.

October 26, 2022, 09:38		#3
Klavoir New Member Join Date: Sep 2021 Posts: 22 Rep Power: 4	Particle diameter 1cm, velocity 70 m/s, no two way coupling, shape factor 0.06

October 26, 2022, 10:36		#4
alainislas Senior Member Alain Islas Join Date: Nov 2019 Location: Mexico Posts: 142 Rep Power: 6	Ok, particles are very big and very very fast!. At such condtions I feel that most likely your particles adopt ballistic behavior. 1) Can you please calculate the Stokes number? 2) Also, calculate the particle settling velocity. 3) Please post images of your domain, or partilcle tracks

October 26, 2022, 10:48		#5
Klavoir New Member Join Date: Sep 2021 Posts: 22 Rep Power: 4	Hi, I will, but can Fluent calculate 1 and 2?

October 26, 2022, 11:00		#6
alainislas Senior Member Alain Islas Join Date: Nov 2019 Location: Mexico Posts: 142 Rep Power: 6	No, you need to estimate them ... These numbers will give you very important information of your system! Please read the theory