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Thursday, April 23, 2020 | History

3 edition of Two-dimensional stability of laminar flames found in the catalog.

Two-dimensional stability of laminar flames

H. S. Mukunda

Two-dimensional stability of laminar flames

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  • 25 Currently reading

Published by National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, For sale by the National Technical Information Service] in [Washington, DC], [Springfield, Va .
Written in English

    Subjects:
  • Laminar flow,
  • Flame -- Stability -- Mathematical models

  • Edition Notes

    Other titlesTwo dimensional stability of laminar flames.
    StatementH.S. Mukunda and J. Philip Drummond.
    SeriesNASA technical paper -- 3131.
    ContributionsDrummond, J. Philip., United States. National Aeronautics and Space Administration. Scientific and Technical Information Program.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15364597M

    Two-dimensional methane-air edge flames propagating in isovelocity, isothermal mixing layers. Solid curves indicate the isothermal (thin) and stoichiometric (thick) surfaces, and dashed curves are used for representative streamlines (from Ann. Rev. Fluid Mech., 47 –, ). Find many great new & used options and get the best deals for Cambridge Monographs on Mechanics: Theory of Laminar Flames by G. S. S. Ludford and J. D. Buckmaster (, Paperback) at the best online prices at eBay! Free shipping for many products!   However, when ϕ>, the increasing of hydrogen fraction is able to stabilize the flame. Besides, the effect of equivalence ratio on the stability of flame is accordant for both methanol-air mixture and methanol-hydrogen-air mixture: the flame stability which obtained from Markstein length decreased with the increasing of equivalence : Xiao Peng, Han Wu, Chia-Fon Lee, Qianbo Sun, Fushui Liu. Stability of Enclosed Laminar Flames Studied in Microgravity ELF flight hardware assembled for testing. In practical combustion systems, the flame is often anchored at the inlet where the fuel is injected into an air duct. This type of system is found in powerplant combustors, gas turbine combustors, and the jet engine afterburner.

    CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): To understand fundamental characteristics of combustion in a small-scale device, the effects of the momentum and heat loss on the stability of laminar premixed flames in a narrow channel are inves-tigated by two-dimensional high-fidelity numerical simulations. A general finding is that momentum loss promotes the.


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Two-dimensional stability of laminar flames by H. S. Mukunda Download PDF EPUB FB2

This numerica l study of the stability of laminar flames specifically addresses the dependence of stability on finite-rate chemistry with low activation energy and variable thermodynamic Two-dimensional stability of laminar flames book. Get this from a library. Two-dimensional stability of laminar flames.

[H S Mukunda; J Philip Drummond; United States. National Aeronautics and Space Administration. Two-Dimensional Stability of Laminar Flames H. Mukunda and J.

Philip Drummond January addsesser the ndencepede of stability on anite-r te mistryche twih alstbe laminar ames could be est up in laboratoires.

Only rectleny have e Two-dimensional stability of laminar flames book of nonnormal. Abstract. This paper reports on the numerical study of the linear stability of laminar premixed flames under zero gravity.

The study specifically addresses the dependence of stability on finite rate chemistry with low activation energy and variable thermodynamic and transport properties.

The calculations show that activation energy and details Cited by: 2. This numerica l study of the stability of laminar flames specifically addresses the dependence of stability on finite-rate chemistry with low activation energy and variable thermodynamic.

Two-dimensional stability of laminar flames. [Washington, DC]: [Springfield, Va: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program ; For sale by the National Technical Information Service] MLA Citation. Mukunda, H.

and Drummond, J. Philip. and United States. The stability of laminar flames was studied numerically and the dependence of stability on finite rate chemistry with low activation energy and variable thermodynamic and transport properties Author: H.

Mukunda and J. Philip Drummond. Theory of Laminar Flames (Cambridge Monographs on Mechanics) This Two-dimensional stability of laminar flames book deals with the structure, generation and stability of flames from a mathematical point of view.

It uses a specific mathematical approach to provide a unified theoretical description of fundamental flame phenomena. Its importance stems from the fact that it provides Format: Paperback. With adiabatic walls, the flame exhibits laminar Bunsen flame behaviour due to both the relationships between the incoming flow velocity and burning velocity, and also the confinement effect Two-dimensional stability of laminar flames book the combustor walls.

Preheating the reactants improves the flame stability at high incoming flow by: ON THE STABILITY OF TWO-DIMENSIONAL PARALLEL FLOWS PART I—GENERAL THEORY* BY C. LIN Guggenheim Laboratory, California Institute of Technology 1. Introduction. The Two-dimensional stability of laminar flames book of the stability of laminar motion and its transition to turbulence dates back to the time of Helmholtz and Reynolds [46], and had.

Laminar flame propagation/quench for a parallel-wall duct Symposium (International) on Combustion, Vol. 20, No. 1 Numerical solution of the two- dimensional equations of laminar flame propagating down a cylindrical tubeCited by: However, the maximum laminar flame speed increases on loading Two-dimensional stability of laminar flames book GT, because typically the effect of an increase of compressor end temperature overcompensates the effect of an increase of pressure.

This means that e.g. flashback risk is increases with load and blow-off stability improves with load. CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): This numerica l study of the stability of laminar flames specifically addresses the dependence of stability on finite-rate chemistry with low activation energy and variable thermodynamic and transport properties.

Laminar Burning Velocity & Flame Stability. Description: Unstretched laminar burning velocity (LBV) is a fundamental property of combustible mixtures Two-dimensional stability of laminar flames book premixed combustion.

Accurate measurement of LBV is necessary for the design of various combustion appliances, development of laminar flamelet models and validation of chemical kinetic. NASA Technical Paper Two-Dimensional Stability of Laminar Flames H.

Mukunda and J. Phihp Drummond Langley Research Center Hampton, V_rgznm Nat¢onarAeronaut=csand. INDEX for INTERNET BOOK ON FLUID DYNAMICS Linear Stability of Laminar Flow (Nng) Flow over a Wavy Wall (Nnh) Small Slip Perturbation (Nni) Sprays (No) Introduction Two-dimensional Shocks (Nsj) References NUMERICAL METHODS (O) Numerical Methods (Oa).

COVID Resources. Reliable information about the coronavirus (COVID) is available from the World Health Organization (current situation, international travel).Numerous and frequently-updated resource results are available from this ’s WebJunction has pulled together information and resources to assist library staff as they consider how to handle coronavirus.

• Laminar premixed flames: Kinematics and Burning Velocity • Laminar premixed flames: Flame Structure of Premixed Laminar Flames 5 • Fuel and oxidizer are convected from upstream • This is the two-dimensional planar version of the axisymmetric Bunsen Size: 2MB.

This paper is concerned with the stability of a two-dimensional laminer wake. The development of small disturbances excited artificially is investigated both experimentally and theoretically. Experiments are made in an experimental water-tank at Reynolds numbers between 10 and for a flat plate and between and 60 for a circular by: The laminar flame speed was obtained by finding a stationary solution of the 12 C flame in a one-dimensional configuration.

The laminar flame solution was used to initialize a two-dimensional interface between a system of cool fuel and hot ash in contact. Dynamics of Laminar Premixed Flames Forced by Harmonic Velocity Disturbances.

The impact of reactants composition and temperature on the flow structure in a wake stabilized laminar lean premixed CH4/H2/air flames; mechanism and scaling. Combustion and Flame, Vol. Development and Analysis of a Novel Two-Dimensional Flame Transfer Cited by:   The stability of the one-dimensional laminar flame propagating with an enthalpy gradient is investigated.

It is shown that flames with zero enthalpy gradient are stable to arbitrary small disturbances. Flames propagating with positive enthalpy gradients are found to be stable and those with negative enthalpy gradients unstable when subject to small disturbances with enthalpy : J.

Adler. Raithby, G Laminar heat transfer in the thermal entrance region of circular tubes and two-dimensional rectangular ducts with wall suction and injection. Intl Author: Vinicius M. Sauer, Fernando F. Fachini, Derek Dunn-Rankin. We performed a comprehensive laser absorption/extinction study of temperature and soot volume fraction (SVF) in C2H4/air premixed sooting flames.

Laser-absorption two-line thermometry at μm provided a temperature uncertainty of 50 K compared with that of 90 K using conventional thermocouples. Laser extinction of soot at nm was first validated against the previous measurements using Cited by: 3.

Flame stability of a fuel jet diffusion flame was studied numerically by using finite rate chemistry. The flow is time dependent and plane two-dimensional, and the chemical reaction is described by simplified, overall one-step kinetics.

The variable parameters are the jet Reynolds number, Re 0, and Damko¨hler number, Da 0; and three types. that alter the local flame temperature and lead to modifications of the local flame speed []. A purely one-dimensional diffusive instability of premixed laminar flames (pulsating.

propagation), has been predicted [6, 7] for mixtures having a very high Lewis number coupled. with a very high activation by: 1. Employing this model to study the stability of a plane flame, they concluded that plane flames are unconditionally unstable.

Yet plane flames are observed in the laboratory. To overcome this difficulty, others have attempted to improve on this model, generally through phenomenological assumptions to replace the assumption of constant by:   Not Available adshelp[at] The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86ACited by: 1.

In combustion engineering and explosion studies, the Markstein number characterizes the effect of local heat release of a propagating flame on variations in the surface topology along the flame and the associated local flame front curvature.

The dimensionless Markstein number is defined as: = where is the Markstein length, and is the characteristic laminar flame thickness. Full text of "An Analytical Model for Non-Uniform Magnetic Field Effects on Two-Dimensional Laminar Jet Diffusion Flames" See other formats AN ANALYTICAL MODEL FOR NON-UNIFORM MAGNETIC FIELD EFFECTS ON TWO-DIMENSIONAL LAMINAR JET DIFFUSION FLAMES M.

Calvert', J. Baker', K. Saito^ and R. Vander Wal^ 'University of Alabama at Birmingham, Birmingham, AL. Linear stability analysis is used to understand the behavior of compressible reacting mixing layers.

The chemistry model is a single step, irreversible, finite rate reaction between the fuel in the upper stream and oxidizer in the lower stream. Laminar flows calculated from the compressible boundary-layer equations serve as inputs to the stability study, and illustrate the structure of laminar Cited by: 3.

An experimental and numerical study on laminar flame characteristics of methane oxy-fuel mixtures highly diluted with CO2 was conducted using a constant volume chamber and CHEMKIN package.

The effects of high CO2 dilution on combustion chemical reaction, flame instability, and flame radiation of CH4/CO2/O2 mixtures were studied. The laminar burning velocities of CH4/CO2/O2 mixtures Cited by: Moreover, burner-stabilized laminar premixed flames are very often used to study chemical kinetics in a combustion environment.

Such flames are effectively one-dimensional and can be made very steady, thus facilitating detailed experimental measurements of temperature and species profiles. Also, laminar flameFile Size: KB.

The process of a laminar flow becoming turbulent is known as laminar–turbulent transition. The main parameter characterizing transition is the Reynolds number. Transition is often described as a process proceeding through a series of stages. M.A.A. Mendes et al. / Combustion and Flame () – Nomenclature A Arrhenius pre-exponential factor as volumetric surface area Cp specific heat capacity D diffusion coefficient E activation energy Hs surface heat transfer coefficient Hv volumetric heat transfer coefficient h specific enthalpy I radiation intensity L length MW molecular weight Qr radiative flux.

A technique for acquiring two-dimensional soot-volume-fraction measurements in laminar flames has been demonstrated. The technique provides a map of very low noise concentration over a range of wavelengths (– nm). A noise level of in extinction and a spatial resolution of 30–40 µm for soot concentration were achieved with an arc lamp source that was filtered to provide.

vibrations on the characteristics of jet diffusion flames C. Kanthasamy, Vasudevan Raghavan* and K. Srinivasan the stability of laminar premixed flames stabilized on a wire. The importance of 80 Effect of low frequency burner vibrations on the characteristics of jet diffusion flames (a) (b) (c) LS 14 13 12 11 10 9 7 8 Vibration exciter.

() Onset of cellular flame instability in adiabatic CH4/O2/CO2 and CH4/air laminar premixed flames stabilized on a flat-flame burner. Combustion and Flame() Influence of radiation losses on the stability of premixed flames on a porous-plug by: Laminar Premixed Flames: Flames Shapes and Instabilities Lecture 9: Laminar Difiusion Flames: Flame Structure stability and pollutant emissions, as it is the case in jet engine combustion chambers, in gas-boilers or in stratifled-charge spark ignition engines.

Stability diagram for lift-off and blowout of a round jet laminar diffusion flame. Sandip Ghosal *, Luc Vervisch * Corresponding author for this work. Lift-off and blowout are characterized by a pair of critical curves in this two-dimensional parameter space the region between which corresponds to a stable lifted flame.

A critical value of Cited by:. Stability of Laminar Flow at Seabed. The flow produced by water waves pdf the laminar boundary pdf above a two-dimensional rough bed is studied analytically.

At low Reynolds numbers the fluid drifts in closed recirculating cells, without dispersion. At high Reynolds numbers, vortex formation occurs for large-scale roughness and sudden jets of fluid are produced at a certain point in each half Cited by: 78 A.N.

Al-Khateeb et al. associated with each linearly independent mode of varying wavelength are identified. In so doing, we extend the recent work of Lu et al.

[6], who included a similar study of the time scales induced by chemistry alone within a hydrogen–air premixed laminar flame, not.Laminar flame speed ebook an intrinsic characteristic of premixed combustible mixtures.

Ebook is the speed at which an un-stretched laminar flame will propagate through a quiescent mixture of unburned reactants. Laminar flame speed is given the symbol s ing to the thermal flame theory of Mallard and Le Chatelier, the un-stretched laminar flame speed is dependent on only three properties of a.