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About: Combustion is a(n) research topic. Over the lifetime, 172336 publication(s) have been published within this topic receiving 1950787 citation(s). The topic is also known as: burning & combusting.

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01 Jan 2001

2,747 citations

Journal ArticleDOI
Abstract: Our current understanding of the mechanisms and rate parameters for the gas-phase reactions of nitrogen compounds that are applicable to combustion-generated air pollution is discussed and illustrated by comparison of results from detailed kinetics calculations with experimental data. In particular, the mechanisms and rate parameters for thermal and prompt NO formation, for fuel nitrogen conversion, for the Thermal De-NOx and RAPRENOx processes, and for NO2 and N2O formation and removal processes are considered. Sensitivity and rate-of-production analyses are applied in the calculations to determine which elementary reactions are of greatest importance in the nitrogen conversion process. Available information on the rate parameters for these important elementary reactions has been surveyed, and recommendations for the rate coefficients for these reactions are provided. The principal areas of uncertainty in nitrogen reaction mechanisms and rate parameters are outlined.

2,661 citations

Journal ArticleDOI
01 Jan 1977
Abstract: Principles of mathematical models as tools in engineering and science are discussed in relation to turbulent combustion modeling. A model is presented for the rate of combustion which takes into account the intermittent appearance of reacting species in turbulent flames. This model relates the rate of combustion to the rate of dissipation of eddies and expresses the rate of reaction by the mean concentration of a reacting specie, the turbulent kinetic energy and the rate of dissipation of this energy. The essential features of this model are that it does not call for predictions of fluctuations of reacting species and that it is applicable to premixed as well as diffusion flames. The combustion model is tested on both premixed and diffusion flames with good results. Special attention is given to soot formation and combustion in turbulent flames. Predictions are made for two C 2 H 2 turbulent diffusion flames by incorporating both the above combustion model and the model for the rate of soot formation developed by Tesner et al., as well as previous observations by Magnussen concerning the behavior of soot in turbulent flames. The predicted results are in close agreement with the experimental data. All predictions in the present paper have been made by modeling turbulence by the k -∈ model. Buoyancy is taken into consideration in the momentum equations. Effects of terms containing density fluctuations have not been included.

2,397 citations

Journal ArticleDOI
Abstract: Most of the particle number emitted by engines is in the nanoparticle range, Dp 50 nm p nm, range. Nanoparticles are typically hydrocarbons or sulfate and form by nucleation during dilution and cooling of the exhaust, while accumulation mode particles are mainly carbonaceous soot agglomerates formed directly by combustion. Emission standards on diesel engines have led to dramatic reductions in particle mass emitted. However, a new HEI study shows that some low-emission diesel engines emit much higher concentrations of nanoparticles than older designs and other low-emission designs. Many recent studies suggest that at similar mass concentrations; nanometer size particles are more dangerous than micron size particles. This has raised questions about whether nanoparticle (number based) emission standards should be imposed. Unlike mass, number is not conserved. It may change dramatically by nucleation and coagulation during dilution and sampling, making it very difficult to design a standard. Furthermore, if nanoparticles are a problem, spark ignition engines may also have to be controlled.

2,143 citations

01 Mar 2000
Abstract: Preface Preface to the Second Edition Preface to the First Edition 1: Introduction 2: Combustion and Thermochemistry 3: Introduction to Mass Transfer 4: Chemical Kinetics 5: Some Important Chemical Mechanisms 6: Coupling Chemical and Thermal Analyses of Reacting Systems 7: Simplifed Conversation Equations for Reacting Flows 8: Laminar Premixed Flames 9: Laminar Diffusion Flames 10: Droplet Evaporation and Burning 11: Introduction to Turbulent Flows 12: Turbulent Premixed Flames 13: Turbulent Nonpremixed Flames 14: Burning of Solids 15: Pollutant Emissions 16: Detonations Appendix A: Selected Thermodynamic Propertiesof Gases Comprising C-H-O-N System Appendix B: Fuel Properties Appendix C: Selected Properties of Air, Nitrogen, and Oxygen Appendix D: Diffusion Coefficients and Methodology for their Estimation Appendix E: Generalized Newton's Method for the Solution of Nonlinear Equations Appendix F: Computer Codes for Equilibrium Products of Hydrocarbon-Air Combustion

2,083 citations

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