Simulation of H2-Air Turbulent Diffusion Flame by the Partial Chemical Equilibrium Method

2007 ◽  
Author(s):  
Kazui Fukumoto ◽  
Yoshifumi Ogami
Keyword(s):  
Chemical Equilibrium ◽  
Molecular Diffusion ◽  
Burning Velocity ◽  
Chemical Species ◽  
Combustion Products ◽  
Turbulent Diffusion Flame ◽  
Combustion Gases ◽  
Equilibrium Method ◽  
Dissipation Model ◽  
Partial Chemical

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.

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

2009 ◽  
Author(s):  
Kazui Fukumoto ◽  
Yoshifumi Ogami
Keyword(s):  
Chemical Equilibrium ◽  
Diffusion Flame ◽  
Turbulent Diffusion ◽  
Combustion Products ◽  
Combustion Model ◽  
Intermediate Species ◽  
Turbulent Diffusion Flame ◽  
Chemical Mechanisms ◽  
Equilibrium Method ◽  
Detailed Chemical

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.

Simulation of a CO-H2-Air Turbulent Diffusion Flame by the Chemical Equilibrium Method With a Few Chemical Reactions

2008 ◽  
Author(s):  
Kazui Fukumoto ◽  
Yoshifumi Ogami
Keyword(s):  
Chemical Reactions ◽  
Chemical Equilibrium ◽  
Diffusion Flame ◽  
Turbulent Diffusion ◽  
Equilibrium Model ◽  
Combustion Products ◽  
Turbulent Diffusion Flame ◽  
Chemical Mechanisms ◽  
Computational Data ◽  
Chemical Equilibrium Model

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.

scholarly journals Calculation of complex chemical equilibrium compositions of composite rocket propellants combustion products

2000 ◽  
Vol 65 (11) ◽  
pp. 803-810
Author(s):  
Milos Filipovic ◽  
Nikola Kilibarda
Keyword(s):  
Chemical Equilibrium ◽  
Chemical Species ◽  
Combustion Products ◽  
Reaction Scheme ◽  
Complex Chemical ◽  
Rocket Propellants ◽  
The World ◽  
Reactive Mixture ◽  
Atomic Species ◽  
Adequate Method

An adequate method for calculating chemical equilibrium in a predominantly gaseous, multi-component reactive mixture was investigated and successfully applied. This method involves the stated equilibrium reaction scheme, including, first, the formation of chemical species, of which concentrations prevail in the mixture, then the formation of gaseous atomic species by dissociation of previous ones, and, finally, the formation of complex chemical species from the atomic species. A computer program, which permits calculations of equilibrium compositions by the iteration procedure, has been developed. The results of calculations have been compared with data obtained by the programs OPHELIE, MICROPEP, and the program SPP, as documented in the NASA-Lewis Code, which is presently the world-wide standard. All comparisons gave satisfactory agreement.

Misbehavior in High Temperature Equilibrium of Water-Gas Reaction

2012 ◽  
Vol 245 ◽  
pp. 346-351
Author(s):  
Radu Dan Rugescu ◽  
Florin Radu Bacaran
Keyword(s):  
Numerical Simulation ◽  
High Temperature ◽  
Chemical Equilibrium ◽  
Solid Propellant ◽  
Combustion Products ◽  
Linearization Method ◽  
Gaseous Products ◽  
Direct Linearization ◽  
Temperature Equilibrium ◽  
Water Gas

The observation that the chemical equilibrium between the combustion products of solid propellant samples within static calorimeters is unexpectedly freezing at high temperatures is proved through a general numerical simulation of the isochoric cooling with chemical reactions between the gaseous products. A proprietary, direct linearization method of thermochemical computation is used that enables following any chemical reaction in equilibrium with high convergence. The observed chemical freezing within calorimeters is proved.

Striking repercussions of the Australian "Black Summer" bushfires on the stratospheric composition and dynamical circulation

2021 ◽  
Author(s):  
Sergey Khaykin ◽  
Bernard Legras ◽  
Silvia Bucci ◽  
Pasquale Sellitto ◽  
Lars Isaksen ◽  
...  
Keyword(s):  
Volcanic Eruptions ◽  
Combustion Products ◽  
Stratospheric Aerosol ◽  
Radiative Balance ◽  
Combustion Gases ◽  
Gaseous Composition ◽  
Stratospheric Composition ◽  
Radiative Transfer Modeling ◽  
Total Column ◽  
Meteorological Analysis

<p>Wildfire-driven pyro-convection (PyroCb) is capable of lofting combustion products into the stratosphere, polluting it with smoke aerosols at hemispheric and yearly scales. This realization has emerged after the record-breaking British Columbia PyroCb event in August 2017 that approached moderate volcanic eruptions in terms of stratospheric aerosol load perturbation. The Australian “Black Summer” bushfires in 2019/20 have surpassed the previous record by a factor of 3 and rivaled the strongest volcanic eruptions in the XXI century. Here we exploit a synergy of various satellite observations, ECMWF meteorological analysis and radiative transfer modeling to quantify the perturbation of stratospheric particulate and gaseous composition, dynamical circulation and radiative balance caused by the Australian New Year’s PyroCb outbreak. One of the most striking repercussions of this event was the generation of several persistent anticyclonic vortices that provided confinement to the PyroCb plumes and preserved them from rapid dilution in the environment. The most intense vortex measured 1000 km in diameter, persisted in the stratosphere for over 13 weeks and lifted a confined bubble of combustion gases, aerosols and moisture to 35 km altitude. It was accompanied by a synoptic-scale ozone hole with the total column reduction by about 30%. The startling consequences of the Australian event provide new insights into climate-altering potential of the wildfires, that have increased in frequency and strength over the recent years.</p>

Analysis of Nitrogen Oxides Formation in CH4/Air Laminar Premixed Flame

2013 ◽  
Vol 750-752 ◽  
pp. 1734-1737
Author(s):  
Jun Xia Zhang ◽  
Bing Biao Yang
Keyword(s):  
Nitrogen Oxides ◽  
Turbulent Diffusion ◽  
Mass Fraction ◽  
Burning Velocity ◽  
Flame Temperature ◽  
Premixed Flame ◽  
Model Parameters ◽  
Turbulent Diffusion Flame ◽  
Chemical Reaction Kinetics ◽  
Combustion Processes

Many combustion processes seriously pollute the environment because of producing nitrogen oxides emission, which abstracts wide attention from researchers. How to reduce nitrogen oxides emission is important to protect the environment. At the present work, a reduction mechanism based on a detailed chemical reaction kinetics mechanism, Gri_Mech3.0 was adopted to analyze nitrogen oxides formation in a CH4/air laminar premixed and turbulent diffusion flames, a two dimensional turbulent diffusion flame was simulated with the EDC model. Parameters were obtained, including flame temperature, burning velocity and mass fraction of nitrogen oxides. The results of laminar premixed flame show that nitrogen oxides emission mainly comes from the thermal and prompt NO mechanisms. A large amount of free radicals O, H and OH produced by combustion processes provide reactants for the reactions of nitrogen oxides formation. Mole fraction of nitrogen oxides increases with the increasing of both flame temperature and chemical equivalence ratios. By contrast, there is a lower mass fraction of nitrogen oxides formation for the fuel-lean flame.

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