Which is the most appropriate particle model

jbritton · August 10, 2010, 12:20

Hi all,

Working on an inhaler that has liquid particles instead or solid particles, interacting with an airflow and the particles in theory being carried to the outlet.

The problem im having is im not sure which model I should be using. I want to take into account that the liquid particles interact to form larger particles and then be able, at the outlet, to show the sizes of the particles that have reached it. The particles at the inlet are assumed to initially be the same size.

The behaviour is inhomogeneous much like the interaction of air bubbles in water, but cant find good values for break up and collation. As this model is designed more with bubbles in mind.

Did consider eularian and modelling the particles as solids, but not sure if its possible to model particles sticking together if they collide?

in short im a bit stuck, if you have any ideas that would be great, if you need any further details please let me know.

ghorrocks · August 10, 2010, 23:09

A lagrangian approach sounds like the way to go here, not eularian. Try a particle tracking approach. That has droplet breakup and coalescence models which may be suitable for you.

Jinx · November 9, 2011, 13:26

Hi Glenn,
sorry to resurrect an old post but this is relevant to a current project I'm working on.
I also need to model droplet agglomeration in a spray but haven't been able to find the Lagrangian coalescense options (particle breakup is available though) in Pre (v13). I want to use the Lagrangian rather than Eulerian approach because of the droplet size distribution at the inlet.
I've been through the help files and have spoken with Ansys support by phone but without success. I'd appreciate any help you can give.

Thanks!

ghorrocks · November 9, 2011, 19:11

It is not an area I have much experience in. Also have a look at the CFX Community site at www.ansys.com as it has some more tutorials.

Other than that you will have to look through the documentation to find what is available.

August 10, 2010, 12:20	Which is the most appropriate particle model	#1
jbritton Member james britton Join Date: Jan 2010 Posts: 38 Rep Power: 16	Hi all, Working on an inhaler that has liquid particles instead or solid particles, interacting with an airflow and the particles in theory being carried to the outlet. The problem im having is im not sure which model I should be using. I want to take into account that the liquid particles interact to form larger particles and then be able, at the outlet, to show the sizes of the particles that have reached it. The particles at the inlet are assumed to initially be the same size. The behaviour is inhomogeneous much like the interaction of air bubbles in water, but cant find good values for break up and collation. As this model is designed more with bubbles in mind. Did consider eularian and modelling the particles as solids, but not sure if its possible to model particles sticking together if they collide? in short im a bit stuck, if you have any ideas that would be great, if you need any further details please let me know.

November 9, 2011, 13:26	lagrangian + coalescence	#3
Jinx New Member John Join Date: Apr 2009 Posts: 6 Rep Power: 17	Hi Glenn, sorry to resurrect an old post but this is relevant to a current project I'm working on. I also need to model droplet agglomeration in a spray but haven't been able to find the Lagrangian coalescense options (particle breakup is available though) in Pre (v13). I want to use the Lagrangian rather than Eulerian approach because of the droplet size distribution at the inlet. I've been through the help files and have spoken with Ansys support by phone but without success. I'd appreciate any help you can give. Thanks!

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August 10, 2010, 23:09		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	A lagrangian approach sounds like the way to go here, not eularian. Try a particle tracking approach. That has droplet breakup and coalescence models which may be suitable for you.

November 9, 2011, 19:11		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	It is not an area I have much experience in. Also have a look at the CFX Community site at www.ansys.com as it has some more tutorials. Other than that you will have to look through the documentation to find what is available.