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Old   May 17, 2002, 16:25
Default modeling of coupled problem
  #1
Godfrey
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Dear all,

I am going to model a catalytic combustion process, which is used to burn off the trace amount of fugitive ethane. The case description are as below: (1) I have to use a hot gases from exsting burners , to raise the temp of my process, I planned to use a configuration like a double pipe heat exchanger, but the gases to be burnt will be entering from the side

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| | burnt gases out

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| | | < - gases to be burnt

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hot gases

My problem is how can I couple the two flow in order to run the calc. , and how could I specify the heat transfer from the hot gases to the cold stream.

I expect your suggestion/experience/thought to direct my modeling of this combustion process. I appreciate your time and expertise.

Godfrey

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Old   May 18, 2002, 08:30
Default Re: modeling of coupled problem
  #2
chiseung
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I suggest this method.

(1) Set the momentum and energy boundary conditions and turn off the "energy" equation in "solve->control".

(2) Solve each flow field separately in a same geometry. An approach to solve this problem is to set one flow field as a solid part and solve the other field. Then export solved flow field data by the function "interpolate" in a Fluent solver. Thus, you can solve the other flow filed in a same manner.(change the solid type continuum and fluid type continuum)

(3) Couple two flow field data in a same geometry and turn off the "flow" equation and turn on the "energy" equation in "solve->control". Then solve energy equation only.

P.S. Above method is valid when there is no natural convection and flow field variables(velocity components) are not governed by temperature.
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Old   May 21, 2002, 12:24
Default Re: modeling of coupled problem
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Godfrey
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In this case there is natural convection on outer fluid side as well as the temperature is very influential in flow field..

Godfrey
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Old   May 21, 2002, 21:04
Default Re: modeling of coupled problem
  #4
chiseung
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Well, how about using "Profile file" in solver? Boundary condition at interface between two regions could be set after solving hot fluid region. Thus you can, I believe, solve the natural convection problem caused by hot fluid region which is spacially separated with cold fluid region.
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Old   May 22, 2002, 14:52
Default Re: modeling of coupled problem
  #5
Godfrey
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Ok I will try this..

but could I use the inner wall as inteface where I can define my boundary condition or I should defined the new interface boundary condition..?? thanx for help
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