Enthalpy Distribution at the Front of an One-Dimensional Laminar Flame

2016 ◽  
Vol 52 (1) ◽  
Keyword(s):  
Laminar Flame ◽  
One Dimensional

The Structure of Laminar Premixed H2-Air Flames at Elevated Pressures

2000 ◽  
Vol 214 (4) ◽  
Author(s):  
M. El-Gamal ◽  
E. Gutheil ◽  
J. Warnatz
Keyword(s):  
Laminar Flame ◽  
Flame Structure ◽  
Ideal Gas ◽  
Fortran Program ◽  
Laminar Flame Speed ◽  
Real Gas ◽  
One Dimensional ◽  
Rocket Propulsion ◽  
Elevated Pressures ◽  
Engine Combustion

In high-pressure flames that occur in many practical combustion devices such as industrial furnaces, rocket propulsion and internal engine combustion, the assumption of an ideal gas is not appropriate. The present paper presents a model that includes modifications of the equation of state, transport and thermodynamic properties. The model is implemented into a Fortran program that was developed to simulate numerically one-dimensional planar premixed flames. The influence of the modifications for the real gas behavior on the laminar flame speed and on flame structure is illustrated for stoichiometric H

Asymptotic analysis of premixed burning with large activation energy

1972 ◽  
Vol 56 (1) ◽  
pp. 81-95 ◽  
Author(s):  
Francis E. Fendell
Keyword(s):  
Laminar Flame ◽  
Lewis Number ◽  
Spherically Symmetric ◽  
Arrhenius Kinetics ◽  
Finite Rate ◽  
Activation Temperature ◽  
One Dimensional ◽  
First Order ◽  
Monomolecular Decomposition ◽  
Kinetics Of

The structure and propagation rates of premixed flames are determined by singular perturbation in the limit where the activation temperature is large relative to other flow temperatures for several basic flows. Specifically, the simple kinetics of an exothermic first-order monomolecular decomposition under Arrhenius kinetics is studied for one-dimensional laminar flame propagation, spherically symmetric quasi-steady monopropellant droplet burning, and other simple geometries. Results elucidate Lewis-number effects, losses owing to fuel gasification processes, and conditions under which the thin-flame approximation is a limit of finite-rate Arrhenius kinetics.

scholarly journals Doping rich ethylene premixed flames: Influence of C3 C5 alcohols on the structure of the steady one-dimensional laminar flame

Fuel ◽  
2022 ◽  
Vol 307 ◽  
pp. 121793
Author(s):  
R. Jalain ◽  
J. Bonnety ◽  
G. Legros ◽  
A. Matynia
Keyword(s):  
Laminar Flame ◽  
Premixed Flames ◽  
One Dimensional

Enthalpy distribution at the front of an one-dimensional laminar flame

2016 ◽  
Vol 52 (1) ◽  
pp. 35-39
Author(s):  
V. A. Bunev ◽  
A. A. Korzhavin ◽  
V. M. Shvartsberg
Keyword(s):  
Laminar Flame ◽  
One Dimensional

The Effect of Diluents on the Formation Rate of Nitrogen Oxide in a Premixed Laminar Flame

2004 ◽  
Author(s):  
Fredrik Hermann ◽  
Thomas Zeuch ◽  
Jens Klingmann
Keyword(s):  
Combustion Temperature ◽  
Laminar Flame ◽  
Premixed Flames ◽  
Inert Gases ◽  
Flame Zone ◽  
Detailed Chemistry ◽  
One Dimensional ◽  
Premixed Laminar ◽  
Thermal Nox ◽  
Premixed Laminar Flame

New high-efficiency power cycles and environmentally friendly cycles have introduced combustion atmospheres that differ from the traditional hydrocarbon-air mixtures. Wet cycles, solid oxide fuel cell with a gas turbine (SOFC-GT), CO2 separation/capture and biogas combustion are processes that involve high concentrations of inert gases such as H2O, CO2 and N2. These new combustion atmospheres have not been well characterized for premixed flames, hence greater interest is attached how NOx formation is affected. At combustion temperatures above 1800 K, NOx emission is dominated by thermal NOx. The thermal NOx mechanism consists of three elementary reactions. The process is known to be exponential in combustion temperature, but it is also comparably slow and thus dependent on the residence time and the temperature in the post-flame zone. To model the flame, code for a one-dimensional flame with detailed chemistry was used. The flame code solves the combustion evolvement for a one-dimensional, premixed laminar flame. Detailed chemistry was used to model the chemical kinetics. NOx production was described by a NOx mechanism, including thermal, prompt and N2O intermediate. Altogether, the mechanisms consisted of 116 species and 713 reactions. The cases investigated were all premixed flames, diluted with either H2O, CO2, N2 or Ar. The cases used a constant combustion temperature of 2000 K and different pressure levels. All cases were investigated at constant inlet air-fuel temperature and varying equivalence ratio. The rate of formation of NO was investigated for both natural gas and hydrogen flames. The rate of formation of NO is reduced by the addition of any diluents at constant combustion temperature if the O-atom concentration is reduced in the high temperature post-flame zone. The computations show equilibrium between O and O2, and the reduced rates of formation of NO (at constant temperature) are thus simply the result of reduction in the product [O2]0.5[N2] in the post-flame zone.

Flame structure and flame reaction kinetics IX. Calculation of properties of multi-radical premixed flamest

1975 ◽  
Vol 346 (1645) ◽  
pp. 261-278 ◽  
Keyword(s):  
Laminar Flame ◽  
Flame Structure ◽  
Partial Equilibrium ◽  
Integration Step ◽  
Quasi Steady State ◽  
Flux Method ◽  
Step Size ◽  
One Dimensional ◽  
Premixed Laminar ◽  
Premixed Laminar Flame

A ‘composite flux’ method is described whereby the solution of multiradical, one dimensional, premixed laminar flame problems may be simplified by the use of appropriate partial equilibrium or quasi-steady state assumptions. In the solution of the problem by integration of the stationary flame equations, the use of these assumptions fulfils two purposes. First, by providing additional relations between the species mole fractions, it reduces the number of independent working hot boundary conditions which must be matched at the start of a successful integration through the flame, thus making the problem more tractable. Secondly, if the composite fluxes are defined appropriately, reduction of integration step size due to ‘stiffness’ problems associated with certain of the reaction steps may be avoided.

An adaptive algorithm for compressible reacting flows using interpolating wavelets

2007 ◽  
Vol 221 (11) ◽  
pp. 1397-1410 ◽  
Author(s):  
R Prosser
Keyword(s):  
Laminar Flame ◽  
Threshold Level ◽  
Reacting Flows ◽  
Collocation Methods ◽  
Adaptive Meshes ◽  
One Dimensional ◽  
Grid Points ◽  
Interpolating Wavelets ◽  
Future Work ◽  
Node Problem

A new wavelet-based method for the simulation of reacting flows on adaptive meshes is presented. The method is based on the removal of grid points whose wavelet coefficients are small with reference to some user-specified threshold. Unlike some other collocation methods, the scheme simulates flow behaviour in the physical (i.e. not transformed) domain, and the wavelets, thus, provide the method by which the derivatives appearing in the transport equations are calculated. The wavelet transformis based on a subtraction algorithm, and circumvents the hanging node problem associated with other adaptive strategies. Interpolating wavelets are applied to a compressible one-dimensional laminar flame problem with time dependent boundary conditions. We find that the resolution of the chemistry distribution is comparatively straightforward. The same is not true of the pressure field, which demonstrates sensitivity to the imposed threshold level. Conclusions and directions for future work are presented based on these findings.

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