Hi Greg or anybody in this forum, On using reaction model, Fluent has provides some reaction models. Currently I work in gasification process. So, to simulate the gasification I interrest in using the model of Mixture Fraction/PDF Formulation instead of using Finite Rate Formulation (using the Arrhenius Rate concept).

Based on your experience, will have the PDF method giving the same result (similar) compare to the Finite Rate Formulation? Or am I wrong using the PDF method to solve the gasification model?

Any responds will be highly appreciate. Thank you Adi

1. It is impossible to calculate 'coal gasification' by Fluent itself. You need UDF. It was very difficult for me and the result was very poor in quantity and quality(It was Fluent 4.x period before Fluent 5.x).

2. It is possible to calculate 'oil(heavy residue etc) gasification' by Fluent itself. PDF modeling approach was fairly good in physical and chemical aspects. I recommend PDF+Gibb's approach because there are many minor species such as CH4, H2S, COS and so on. And, fast chemistry assumption is, I think, very realisitic because the flame temperature for gasification is very high for coal/oil gasification. Utah and BYU's approach is the same. You can refer PCGC program which has been developed at ACERC in BYU.

Sincerely, Jinwook

Hi Jinwook Tahnks for your responds. It is quite true. It is difficult to get the reasonable result using Finite Rate Formulation using Fluent. I got headache! Now I am trying using Mixture Fraction/PDF Formulation to solve the (biomass) Gasfication model.

You mentioned Gibb's approach or Gibb's free energy, it means that the equilibrium model is more suitable also for reaction mechanism of the gasification? Can you please send me some copies of the published paper regarding the application of PDF method?

Regards Adi

1. Yes, I think that 'PDF'+'Gibb's Free Energy Minimization' method is suitable for gasification simulation.

2. I've punlished my own papers for oil(heavy residue oil) gasification only at Korea domestic journal. You can find couple of papers published by research group of BYU(Brigham Young University) and Utah University from internationla journal. I do not have them with me right now.

Sincerely, Jinwook

Hi Adi,

Welcome to the club...

I do agree with Jin... it is not possible for Fluent to model coal gasification directly... I am currently using FG-DVC model of AFR Inc... I have developed a model using C++ for a single large coal particle combustion model which include the FG-DVC submodel...

My next stage of work is to incorporate this model via UDF to Fluent... I think Greg is well advance in this work... I suggest that you keep in touch with him...

Hi Stanley,

I'm not sure if you were referring to me, but my models are simplified compared to the FG-DVC model. In the sense I don't track the evolution of particle composition in time. Looking at them both the FG-DVC and CPD models require a lot of pde's to get a solution. I started out with tracking species in time, say FC, VM, Ash and Moisture but only for a small-scale model. At a larger scale I've resigned myself to the fact that that's a lot of work and in my case there are many uncertainties in the inputs for those models.

However, I'm sure your application is quite different. In fact, do you intend coupling that model to the Langrangian phase or to an Eulerian solid phase?? And how many extra pde's do you solve. I read that in the updated version of F-Bed by Hobbs, they use up to 192 ode's - I don't think Fluent can handle that many!

Greg

[onlylno]

Originally Posted by Stanley
;97638

Hi Adi,

Welcome to the club...

I do agree with Jin... it is not possible for Fluent to model coal gasification directly... I am currently using FG-DVC model of AFR Inc... I have developed a model using C++ for a single large coal particle combustion model which include the FG-DVC submodel...

My next stage of work is to incorporate this model via UDF to Fluent... I think Greg is well advance in this work... I suggest that you keep in touch with him...

I am doing this kind of work. Can we talk?