Simulation of H2-Air Turbulent Diffusion Flame by the Combustion Model Using Chemical Equilibrium Combined With the Eddy Dissipation Concept

Author(s):  
Kazui Fukumoto ◽  
Yoshifumi Ogami

This research aims at developing a turbulent diffusion combustion model based on the chemical equilibrium method and chemical kinetics for simplifying complex chemical mechanisms. This paper presents a combustion model based on the chemical equilibrium method and the eddy dissipation concept (CE-EDC model); the CE-EDC model is validated by simulating a H2-air turbulent diffusion flame. In this model, the reaction rate of fuels and intermediate species is estimated by using the equations of the EDC model. Further, the reacted fuels and intermediate species are assumed to be in chemical equilibrium; the amount of the other species is determined from the amount of the reacted fuels, intermediate species, and air as reactants by using the Gibbs free energy minimization method. An advantage of the CE-EDC model is that the amount of the combustion products can be determined without using detailed chemical mechanisms. The results obtained by using this model were in good agreement with the experimental and computational data obtained by using the EDC model. Using this model, the amount of combustion products can be calculated without using detailed chemical mechanisms. Further, the accuracy of this model is same as that of the EDC model.

2008 ◽  
Author(s):  
Kazui Fukumoto ◽  
Yoshifumi Ogami

The aim of our research is to build a model that can evaluate the amount of combustion products by using the chemical equilibrium method with a few chemical reactions. This paper presents an eddy dissipation concept/chemical equilibrium model (EDC/CE) and validates it by simulating a CO-H2 air turbulent diffusion flame. The obtained results were compared with Correa’s experimental data, Gran’s computational data, and the computational data obtained by using a chemical equilibrium model in FLUENT. An advantage of the EDC/CE model is that the amount of any combustion products are obtained without using detailed chemical mechanisms. The results obtained by the EDC/CE model are in good agreement with the reference data. With the combustion model that we have developed, the amount of combustion products can be calculated without detail chemical mechanisms, and the accuracy of this model is in the same order as that of the EDC model.


Author(s):  
Kazui Fukumoto ◽  
Yoshifumi Ogami

This paper describes an application of the partial chemical equilibrium method considered chemical kinetics in computational fluid dynamics (CFD). In this method, fuels and oxidants are mixed at a turbulent rate so that a mixture gas of fuel and oxygen is generated. Next, the mixture gas of fuel and oxygen is burnt by molecular diffusion thereby resulting in combustion gases. The turbulent mixture rate is estimated by the eddy dissipation model and the burning velocity is evaluated by the Arrhenius equation. Finally, the combustion products are calculated by the chemical equilibrium method by using the combustion gases. One of the advantages of this method is its ability to calculate the combustion products without using chemical equations. The chemical equilibrium method requires only thermo-chemical functions (specific heat, standard enthalpy, etc). This method can be applied to incinerators or some complex combustion instruments and it can predict the intermediate chemical species of dioxins, etc.


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