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-   -   2D simulation for mixing two non-reacting gases (https://www.cfd-online.com/Forums/fluent/90241-2d-simulation-mixing-two-non-reacting-gases.html)

 arun.mechie July 5, 2011 08:11

2D simulation for mixing two non-reacting gases

I want to carry out a simulation for mixing two non-reacting gases, methane and hydrogen. Methane is allowed to enter a mixing chamber with a diameter of 35mm by a tube of 7 mm dia and hydrogen is allowed to enter the chamber from two tubes of 7mm dia normal to the methane tube. Both the gases are at 200 bar.
Can anyone suggest me how to do the simulation for these gases. I need minimum pressure drop and maximum and homogenuity in the resulting gases.

The mutliphase models that should be used are : Volume of Fluid or Eulerian.
eulerian is a bit slower.

 arun.mechie July 5, 2011 09:51

Quote:
 Originally Posted by AdrienL (Post 314762) The mutliphase models that should be used are : Volume of Fluid or Eulerian. eulerian is a bit slower.
I am using two diff gases(methane and hydrogen for my model). I dont think the multiphase model would be useful here.

My bad, you can't use Volume of Fluid but Eulerian works perfectly

 SerSe December 13, 2011 16:51

Dear Arun,

how did you solve your mixing analysis?
I am facing the same problem, I have a nozzle ejecting air into a pipe containing gas. I am interested in the mixing of the two materials. How can I handle this? Which model should I activate in Fluent (Transport of species, Eulerian, VOF, ...)?

Sergio

 doronzo December 14, 2011 13:01

Re

Hello

Why not multispecies (with no reaction) only? For two gas species, you'll have two continuity equations, but only one for momentum, and energy. The turbulent mixing will do the rest

Regards

 SerSe December 16, 2011 06:21

Dear Doronzo,

I am not familiar with multispecies model, but it seems to me the Eulerian multiphase model can account for fluid-fluid mixing (even if both fluids are gases) and the multispecies is dedicated more to chemical species (i.e., for each gas I have to define its chemical composition).
Since I am not interested in single species distribution (each gas is composed of several species), I guess the multiphase is the most appropriate.

What is your opinion on this?

Regards

 doronzo December 16, 2011 08:50

Re

are the two fluids miscibile or immiscible? regards

 SerSe December 16, 2011 11:05

One fluid is air, the other is syngas composed of n2, 02, co, co2 and other species. They are miscible in the sense that they can penetrate each other but they are not reacting.

Which model would you use, multispecies or multiphase? If you suggest to use the multispecies, should I define each single species for both fluids?

Thank you very much!

Serse

 doronzo December 16, 2011 15:48

Re

I would use multispecies, with two species, one/fluid. The non-reacting mixing will probably depend on turbulent mixing, and in each cell you will have volume fractions for the two fluids.

In case of immiscible fluids, VoF would be probably necessary, although Eulerian multiphase can be also used, but I would use multispecies only

 SerSe December 20, 2011 09:11

Hello,

I am using the species transport model how you suggested, and it works perfectly! I specified one syngas-air mixture where syngas is composed of one fluid (syngas) and air is composed of two fluids (nitrogen and oxygen as from Fluent database). The mixture has ideal gas behaviour for density calculation as air is entering the system through a nozzle where it undergoes adiabatic expansion. The solver is density-based. I have also included the k-e realizable turbulent model.

Next step will be to include transfer of heat from/to walls by convection and radiation. If you have any tip to provide on this, please reply.

Thank you very much.

 shahrouzmoh November 22, 2012 19:18

mixing air and methan in a tee

Hi
I am working on a project, air and methane are entering a tee from two different sides and the mixture is leaving the geometry from the other side, can eny one help me with it?

 arun.mechie April 26, 2013 16:14

Hello every1.. I have stopped working on Fluent. And sorry every1 for not being able to reply as I have not used this forum for quite a long time

 mamalili January 30, 2015 04:53

qubic chamber with hydrogen release

Hi every1
I have similar prob
my problem is a qubic chamber filled by air and hydrogen leaks to it from a small hole in the bottom,
what model is appropriate 4 this prob
regards

 sbkashif July 27, 2015 05:59

Non reactive gaseous simulation

Hello

I intend to study the mixing of two gases in aa non-reactive environment and i find the current discussion related to the activity I am pursuing.

Firstly, as per the discussion till now in this forum, I guess species model is more appropriate.

Secondly, using the model and the boundary conditions, which result could we expect and how would we quantify the extent of mixing using these results.

Lastly, can anyone upload a related tutorial in Fluent/CFX platform.

 santosh.PINTU August 16, 2015 11:25

Gas Mixing Problem

[QUOTE=SerSe;336468]Hello,

I am trying to solve a problem that you have attended earlier. On this regard I need your suggestion and guideline. I am trying to check the turbulence intensity of two non reacting fluid after mixing and each of them have different composition. AIR- Biogas Mixing in a T- Type Mixer. I am not able to edit the Material and the parameters of biogas in Ansys. Please suggest me which model I should prefer. I am trying to solve it with species transport model but net able to set the properties of the biogas and air science there is no provision. please suggest me some material which is specific on this regard.

Thank you very much.

 santosh.PINTU August 16, 2015 11:26

Quote:
 Originally Posted by SerSe (Post 336468) Hello, I am using the species transport model how you suggested, and it works perfectly! I specified one syngas-air mixture where syngas is composed of one fluid (syngas) and air is composed of two fluids (nitrogen and oxygen as from Fluent database). The mixture has ideal gas behaviour for density calculation as air is entering the system through a nozzle where it undergoes adiabatic expansion. The solver is density-based. I have also included the k-e realizable turbulent model. Next step will be to include transfer of heat from/to walls by convection and radiation. If you have any tip to provide on this, please reply. Thank you very much.
I am trying to solve a problem that you have attended earlier. On this regard I need your suggestion and guideline. I am trying to check the turbulence intensity of two non reacting fluid after mixing and each of them have different composition. AIR- Biogas Mixing in a T- Type Mixer. I am not able to edit the Material and the parameters of biogas in Ansys. Please suggest me which model I should prefer. I am trying to solve it with species transport model but net able to set the properties of the biogas and air science there is no provision. please suggest me some material which is specific on this regard.

 kavehsh August 3, 2016 08:31

help

Hi there, I'm working on the same project. and I have some problems.
which model of turbulence model is better? k-e or k-w
and should I change the constant of intensity of turbulence? how?

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