Multiphase models

Bhoomin17 · December 1, 2016, 07:41

Hello,

I am trying to simulate mixing of air and methane in a counterflow reactor in fluent. Now, I'm a little confused about which multiphase model to use? Should I go for mixture as it deals with mixture momentum equations and prescribes relative velocities to describe the dispersed phases or opt for VOF or Eulerian?
Any help would be appreciated.

SPH_CFD · December 3, 2016, 07:12

Quote:

Originally Posted by Bhoomin17

Hello,

I am trying to simulate mixing of air and methane in a counterflow reactor in fluent. Now, I'm a little confused about which multiphase model to use? Should I go for mixture as it deals with mixture momentum equations and prescribes relative velocities to describe the dispersed phases or opt for VOF or Eulerian?
Any help would be appreciated.

It depends on mass fraction and what you want to get in model
If mass fraction of air is small, you can use mixture model otherwise Euler-Euler model.
Besides, you should consider what kind of results you want to get in model. For example, if you think catch interface is important, so go with VOF.

But in your case, maybe interface is not so important. So, mixture model or Eulerian is enough

sina_mech · December 3, 2016, 14:29

As Quang mentioned, if you're not interested in interface-capturing, mixture model would be a better (easier) choice. Just make sure you reach a good convergence, cause fore example sometimes you see converging residuals, but you second phase has not even reached to the outlet of the domain (if an outlet exists though!)

Bhoomin17 · December 3, 2016, 15:37

Thank you for your replies. I appreciate it, and I do have an outlet. Right now, I am just trying to figure out how well these two liquids will mix. I also have to do the combustion analysis, but, that comes later on. Also, if it's possible, can you explain me how this phase thing works? I'm not sure if I understand it correctly.

sina_mech · December 3, 2016, 15:42

which part is confusing? Please specify.

Bhoomin17 · December 3, 2016, 15:45

Like, if I assign air as phase 1 and methane as phase 2 will the results differ if I put methane as phase 1 and air as phase 2?

SPH_CFD · December 4, 2016, 08:14

https://www.sharcnet.ca/Software/Flu...ug/node890.htm

Guys, Please take a look. It is very in details for you

Bhoomin17 · December 4, 2016, 23:10

Thank you.

December 1, 2016, 07:41	Multiphase models	#1
Bhoomin17 New Member Bhoomin Chauhan Join Date: Sep 2016 Posts: 9 Rep Power: 9	Hello, I am trying to simulate mixing of air and methane in a counterflow reactor in fluent. Now, I'm a little confused about which multiphase model to use? Should I go for mixture as it deals with mixture momentum equations and prescribes relative velocities to describe the dispersed phases or opt for VOF or Eulerian? Any help would be appreciated.

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December 3, 2016, 14:29		#3
sina_mech Senior Member SinaJ Join Date: Nov 2009 Posts: 136 Rep Power: 16	As Quang mentioned, if you're not interested in interface-capturing, mixture model would be a better (easier) choice. Just make sure you reach a good convergence, cause fore example sometimes you see converging residuals, but you second phase has not even reached to the outlet of the domain (if an outlet exists though!)

December 3, 2016, 15:37		#4
Bhoomin17 New Member Bhoomin Chauhan Join Date: Sep 2016 Posts: 9 Rep Power: 9	Thank you for your replies. I appreciate it, and I do have an outlet. Right now, I am just trying to figure out how well these two liquids will mix. I also have to do the combustion analysis, but, that comes later on. Also, if it's possible, can you explain me how this phase thing works? I'm not sure if I understand it correctly.

December 3, 2016, 15:42		#5
sina_mech Senior Member SinaJ Join Date: Nov 2009 Posts: 136 Rep Power: 16	which part is confusing? Please specify.

December 3, 2016, 15:45		#6
Bhoomin17 New Member Bhoomin Chauhan Join Date: Sep 2016 Posts: 9 Rep Power: 9	Like, if I assign air as phase 1 and methane as phase 2 will the results differ if I put methane as phase 1 and air as phase 2?

December 4, 2016, 08:14		#7
SPH_CFD Member Quang Le Dang Join Date: Jun 2012 Posts: 61 Rep Power: 13	https://www.sharcnet.ca/Software/Flu...ug/node890.htm Guys, Please take a look. It is very in details for you

December 4, 2016, 23:10		#8
Bhoomin17 New Member Bhoomin Chauhan Join Date: Sep 2016 Posts: 9 Rep Power: 9	Thank you.