three phase problem in packed bed
 

I am simulating three-phase problem - air, water cocurrent flow through a bed of solid catalyst. First step is looking at the flow behavior like pressure drop, gas void fraction, etc. Should i use two phase simulation with porous zone or true three phase simulation? What kind of model is approprate, Mixture or Eulerian?

Re: three phase problem in packed bed
 

I think you should simulate your system using a three phase simulation, specifing the granular phase with the Packed Bed option enabled (FLUENT 6.1).

I'd suggest the Eulerian model.

Hi

ap :)

Re: three phase problem in packed bed
 

i see, i used fluent 5.2, i dont know if new fluent can simulate 3 phase,:P

Re: three phase problem in packed bed
 

Yes. Fluent 6.0 and 6.1 implement the Eulerian-Eulerian multiphase model, which allows you to model a general number of phases, including granular ones, which can be described with the kinetic theory approach.

Anyway the option for packed bed is only present in FLUENT 6.1.

Hi :)

ap

Re: three phase problem in packed bed
 

thank you, do you know the journal to guide for modeling heat transfer in paralel flow pipe?

Re: three phase problem in packed bed
 

Thank you, AP. Have you tried this problem before? Did you experience any convergence problem with 3 phase Eulerian model? What do you think if i use two phase model like VOF with the porous media option on?

I am a little late to reply. But I think you should use two phases and eulerian to do with your problem.

Hi,

I've tried to model a Trickle Bed reactor by both options 1) Three phase eulerian 2) 2 phase eulerian with porous media. Both simulations had convergence problem.

Problem for Gas & liquid phase is how to define the bubble dia considering gas is continuous phase.

For the 3 phase case, I patched solid vol fraction i.e. (1 - bed voidage ) in the solution domain, but to my surprise, solid volume fraction keeps on changing and eventually get replaced by the liquid & gas which is not correct.

Anybody has any clue?

Response will be appreciated.

Try to set the solid to be packed bed

CFD in Trickle Bed reactor
 

Hi,

I've tried to model a Trickle Bed reactor by both options 1) Three phase eulerian 2) 2 phase eulerian with porous media. Both simulations had convergence problem.

Problem for Gas & liquid phase is how to define the bubble dia considering gas is continuous phase.

For the 3 phase case, I patched solid vol fraction i.e. (1 - bed voidage ) in the solution domain, but to my surprise, solid volume fraction keeps on changing and eventually get replaced by the liquid & gas which is not correct.

Anybody has any clue?

Response will be appreciated.

email- omar.rahul51@gmail.com

What about fixing the velocities of your solid particles in the whole domain to 0?

Also I have read that two phase flow with porous media does not work well in FLUENT, unless you set relative permeabilities via UDF.

The question is that I have tried to model a fixed bed inside a tube using:

1 Three phase flow
2 Single phase flow (with species transport describing my mixture) and porous media for the fixed bed of solid particles using Blake-Kozeny equations for alpha and C1 (based on solid concentration and diameter of solid particles), but I have found that quite different values (for pressure drop for instance) are provided by each model.

Am I missing something or should this two models lead to similar results?