Liquid-Solid Modeling

safikhani_hamed · August 11, 2011, 05:54

Dear friends,
I am going to modeling a simple tube containing water and solid particles using eulerian-eulerian model but unfortunately I do not get good results and I get very bad results , I mean the particles at the end of the tube collect at the top of the tube , how ever that the density of particles are much more than that of water and the particles should collect at the bottom of the tube, I do not know what is the problem, can any body help me ? is there any tutorial about liquid-soid modeling ? I have read the examples of tutorial.

ghorrocks · August 11, 2011, 07:55

I think there are some tutorials on eular-eular modelling which come with CFX.

If the particles go up not down are you sure you have the gravity vector in the correct direction?

safikhani_hamed · August 11, 2011, 08:11

yes I have defined the gravity direction correctly.

safikhani_hamed · August 11, 2011, 11:43

Dear Glenn,

I checked the problem, I found the reason in fact I do not know why the software automatically change the particle material to air, do you know what is the problem ?

ghorrocks · August 11, 2011, 19:19

You have not specified your materials correctly. Have a look at the CFX tutorials on how to specify materials.

juliom · August 16, 2011, 08:48

Colleague work with the discret model (lagrange).
good Luck

ghorrocks · August 16, 2011, 18:27

Why use particle tracking? The eularian approach is a valid way of modelling particle laden flows and for densely packed flows the lagragian approach is not suitable.

Hamed has not said anything which suggests the eularian approach is not suitable.

juliom · August 16, 2011, 19:17

Glenn,
You are right, but when you have small quantities of a dispresed phase, you should use the disscrete model.
Indeed both approach are valid, but Lagrange model will work better, you can read the FLUENT tutorial, where they explain very well about the stokes number and the other propierties which you have to evaluate before selecting the suitable model. In theory Every model would work, but in the reality just one will give you the results you need.

August 11, 2011, 05:54	Liquid-Solid Modeling	#1
safikhani_hamed Member Hamed Join Date: Oct 2009 Posts: 64 Rep Power: 16	Dear friends, I am going to modeling a simple tube containing water and solid particles using eulerian-eulerian model but unfortunately I do not get good results and I get very bad results , I mean the particles at the end of the tube collect at the top of the tube , how ever that the density of particles are much more than that of water and the particles should collect at the bottom of the tube, I do not know what is the problem, can any body help me ? is there any tutorial about liquid-soid modeling ? I have read the examples of tutorial.

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August 11, 2011, 07:55		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,701 Rep Power: 143	I think there are some tutorials on eular-eular modelling which come with CFX. If the particles go up not down are you sure you have the gravity vector in the correct direction?

August 11, 2011, 08:11		#3
safikhani_hamed Member Hamed Join Date: Oct 2009 Posts: 64 Rep Power: 16	yes I have defined the gravity direction correctly.

August 11, 2011, 11:43		#4
safikhani_hamed Member Hamed Join Date: Oct 2009 Posts: 64 Rep Power: 16	Dear Glenn, I checked the problem, I found the reason in fact I do not know why the software automatically change the particle material to air, do you know what is the problem ?

August 11, 2011, 19:19		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,701 Rep Power: 143	You have not specified your materials correctly. Have a look at the CFX tutorials on how to specify materials.

August 16, 2011, 08:48		#6
juliom Senior Member Julio Mendez Join Date: Apr 2009 Location: Fairburn, GA. USA Posts: 290 Rep Power: 18	Colleague work with the discret model (lagrange). good Luck

August 16, 2011, 18:27		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,701 Rep Power: 143	Why use particle tracking? The eularian approach is a valid way of modelling particle laden flows and for densely packed flows the lagragian approach is not suitable. Hamed has not said anything which suggests the eularian approach is not suitable.

August 16, 2011, 19:17		#8
juliom Senior Member Julio Mendez Join Date: Apr 2009 Location: Fairburn, GA. USA Posts: 290 Rep Power: 18	Glenn, You are right, but when you have small quantities of a dispresed phase, you should use the disscrete model. Indeed both approach are valid, but Lagrange model will work better, you can read the FLUENT tutorial, where they explain very well about the stokes number and the other propierties which you have to evaluate before selecting the suitable model. In theory Every model would work, but in the reality just one will give you the results you need.