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-   -   help!!!how to solve multiphas flow combustione (http://www.cfd-online.com/Forums/fluent/28043-help-how-solve-multiphas-flow-combustione.html)

king J November 22, 2000 10:17

help!!!how to solve multiphas flow combustione
 
Hi friends:

Now I want to solve one multiphas flow combustion problem.But the multiphas flow models in flunet5.4 cannot apply to species mixing and reaction flow.

How can I solve the problem? Can User Define Scalar solve it??

Thanks

Greg Perkins November 22, 2000 19:54

Re: help!!!how to solve multiphas flow combustione
 
I think it depends on your problem - please specify more details.

Greg

king J November 22, 2000 22:45

Re: help!!!how to solve multiphas flow combustione
 
Thank you for you replay.

I am simulating some mutiphase combustion problems.It is filled with fuel gase in a tank.I want to spray much liquid oxidizer in the tank. Then the combustion is going on.The present analysis adopts the continum formulation of gas-phase and droplet-phase flows.The governing equations include multiphase conservation equations of mass,momentum,energy,species turbulent kinetic energy,and turbulent dissipation rate.How can I solve the problem?

I am a new fluent user.But I cannot find some way to sovle it.

Thanks.I am waiting for your help.

my e-mail:uoyevolun@yahoo.com.cn

Greg Perkins November 22, 2000 23:25

Re: help!!!how to solve multiphas flow combustione
 
Well your problem is quite a difficult one. Assuming you can't use a Lagrangian method to track the droplets/particle/bubbles and their interaction with a gas phase and reaction due to high particle/bubble loading or volume fraction then I don't think there is a Fluent version which can solve this problem "out-of-the-box". You can use the Eulerian multiphase model in Fluent v4.5 to model the flow and heat transfer of the two phases and species reaction in one of the phases, but if you want to model gas-liquid reaction you will need to write your own user model for this, which can be time consuming.

I suggest talking to your Fluent technical support people about the best approach for your problem.

Regards

Greg

king J November 23, 2000 03:04

Re: help!!!how to solve multiphas flow combustione
 
Mr Greg

Thank you .I have some other problem to ask you.

One problem is whether the mesh in fluent5.4 can slide with the regression of solid fuel surface or not.

The other problem is whether the boundary condition in fluent5.4,such as T,can change with the computation or not.

Thanks.


Greg Perkins November 23, 2000 18:52

Re: help!!!how to solve multiphas flow combustione
 
Ahhhh....fluent 4.5 does include a moving/deforming mesh facility - but you must prescribe the mesh deformation prior to calculations - thus its not reall y possible to have the mesh regrid/move/deform based on the solution of your problem. Being a structured grid can be limiting.

I'm pretty sure you can specify the boundary conditions in user code (somehow).

...This is exactly the problem I had - since I wanted to solve for the chemical reaction and consumption of a solid fuel. There's no easy solution to this problem with the curent fluent releases - after trying 5.x then 4.5 I've gone back to 5.4 and use the solution adaption regridding facility in 5.4. But to model the Eulerian-Eulerian model in 5.4 I've had to write a fair amount of code and of course a gas-solid reaction module. Some of these issues will be solved with fluent 6, they tell me, but I suspect while it will be easier - it still won't be easy.

Have fun

Greg


king J November 26, 2000 20:37

Re: help!!!how to solve multiphas flow combustione
 
Mr Greg :

Thank you for so much help.

Now I want simulate some fluid flowing through a symmetry tube.And I want to use 2D solver in fluent5.4. How can I mesh the tube?There is also boundary Layer in the tube.How can I mesh boundary? Please tell me the steps.Thank you

Greg Perkins November 26, 2000 23:43

Re: help!!!how to solve multiphas flow combustione
 
You can do that in Gambit - you should read the manuals before asking lots and lots of questions.

Regards

Greg


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