The paper presents numerical simulations of a core methane jet diffusion flame with a fuel lean mixture (consisting of methane and hydrogen, in different proportions) in the co-flow. A comprehensive numerical model, which employs a detailed chemical kinetic mechanism with 25 species and 121 reaction steps, variable thermo-physical properties, multi-component diffusion and an optically thin radiation sub-model, has been used. The results of the numerical model are validated against the experimental data from literature. The validated model is used to study the characteristics of core methane jet diffusion flames with methane and hydrogen in the co-flow. A detailed study of various quantities such as temperature, sensible enthalpies of combustion and nitric oxide emissions is carried out, for different compositions of the fuel in the co-flow oxidizer stream. The co-flow composition which results in minimum nitric oxide emissions is examined. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Vasudevan Raghavan

Department of Mechanical Engineering

S. Arun

S. Raghuram

R. Sreenivasan

DETAILED CHEMICAL KINETIC

Diffusion Flame

Fuel mixtures

NITRIC OXIDE EMISSIONS

RADIATION MODELS

combustion

Fuels

Hydrogen

Methane

Nitric oxide

Numerical models

Diffusion

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

International Journal of Hydrogen Energy

Numerical and experimental investigations of unconfined methane-oxygen laminar premixed flames are presented. In a lab-scale burner, premixed flame experiments have been conducted using pure methane and pure oxygen mixtures having different equivalence ratios. Digital photographs of the flames have been captured and the radial temperature profiles at different axial locations have been measured using a thermocouple. Numerical simulations have been carried out with a C2 chemical mechanism having 25 species and 121 reactions and with an optically thin radiation sub-model. The numerical results are validated against the experimental and numerical results for methane-air premixed flames reported in literature. Further, the numerical results are validated against the results from the present methane-oxygen flame experiments. Visible regions in digital flame photographs have been compared with OH isopleths predicted by the numerical model. Parametric studies have been carried out for a range of equivalence ratios, varying from 0.24 to 1.55. The contours of OH, temperature and mass fractions of product species such as CO, CO 2 and H 2O, are presented and discussed for various cases. By using the net methane consumption rate, an estimate of the laminar flame speed has been obtained as a function of equivalence ratio. © 2012 Taylor and Francis Group, LLC.

Combustion Theory and Modelling

An investigation of flame zones and burning velocities of laminar unconfined methane-oxygen premixed flames

Numerical investigations of burning and emission characteristics of laminar methane diffusion flames in a coflowing preheated oxidizer are presented. The preheated oxidizer stream contains hot products of combustion, such as carbon dioxide and water vapor, along with oxygen and nitrogen, and is equivalent to that obtained in an exhaust gas recirculation process. Numerical simulations are carried out using a numerical model incorporated with a C2 chemical mechanism having 25 species and 121 reactions and an optically thin radiation submodel. The numerical results are validated against the experimental results for methane-air coflow flames reported in the literature. Parametric studies have been carried out by changing the temperature and composition of the coflowing oxidizer stream. The effects of these parameters on flame height, flame stability, and emission characteristics are analyzed. It is observed that the increase in the temperature of the oxidizer has a stabilizing effect on the flame, even with a lesser concentration of oxygen in the oxidizer. By investigating the stable flame cases in which a maximum temperature of around 2000 K is achieved, it can be concluded that the preheated oxidizer stream (higher temperature and reduced oxygen) helps in significant reduction of emissions such as nitric oxide and carbon monoxide. © 2010 by Begell House, Inc.

International Journal of Energy for a Clean Environment

Numerical investigation of burning and emission characteristics of laminar methane diffusion flames in preheated oxidizer

Fuel Cells

Three-dimensional Modeling of Gas Purge in a Polymer Electrolyte Membrane Fuel Cell with Co-flow and Counter-flow Pattern

Energy & Fuels

Effects of Burned Gas Recirculation on NOx Emissions from Natural Gas–Hydrogen–Oxygen Flames in a Burner with Separated Jets

Effect of H2O Vapor on NO Reduction by CO: Experimental and Kinetic Modeling Study

Effect of hydrogen addition in the co-flow of a methane diffusion flame in reducing nitric oxide emissions

Journal	International Journal of Hydrogen Energy
ISSN	03603199
Open Access	No