Flame spread

About: Flame spread is a research topic. Over the lifetime, 1907 publications have been published within this topic receiving 28698 citations. The topic is also known as: surface burning characteristics rating & Flame Spread Index.

Mixing and chemical reaction in steady confined turbulent flames

Abstract: A calculation procedure has been developed for solving the partial parabolic differential equation of turbulent flame spread. This procedure has been applied to the spread of flame behind a baffle in a plane-walled duct, with two distinct models for the kinetics of the reaction. In the first model, the time-mean reaction rate is related to the time-mean concentrations and temperature at the point in question by a bimolecular Arrhenius expression. In the second model, the local reaction rate is taken to depend also on the rate of break-up of the eddies by fits the experiemntal data better than the first; the eddy-break-up term appears to be essential if the dominance of hydrodynamic processes is to be correctly simulated. A third model of turbulent combustion is also described. It involves the calculation of the magnitude of the fluctuating concentrations, and correctly predicts themain features of turbulent diffusion flames. One of its implications is a finite reaction-zone thickness, even through there is no chemical-kinetic resistance.

Fundamentals of Fire Phenomena

Abstract: Preface. Nomenclature. 1 Introduction to Fire. 1.1 Fire in History. 1.2 Fire and Science. 1.3 Fire Safety and Research in the Twentieth Century. 1.4 Outlook for the Future. 1.5 Introduction to This Book. 2 Thermochemistry. 2.1 Introduction. 2.2 Chemical Reactions. 2.3 Gas Mixture. 2.4 Conservation Laws for Systems. 2.5 Heat of Formation. 2.6 Application of Mass and Energy Conservation in Chemical Reactions. 2.7 Combustion Products in Fire. 3 Conservation Laws for Control Volumes. 3.1 Introduction. 3.2 The Reynolds Transport Theorem. 3.3 Relationship between a Control Volume and System Volume. 3.4 Conservation of Mass. 3.5 Conservation of Mass for a Reacting Species. 3.6 Conservation of Momentum. 3.7 Conservation of Energy for a Control Volume. 4 Premixed Flames. 4.1 Introduction. 4.2 Reaction Rate. 4.3 Autoignition. 4.4 Piloted Ignition. 4.5 Flame Speed, Su. 4.6 Quenching Diameter. 4.7 Flammability Limits. 4.8 Empirical Relationships for the Lower Flammability Limit. 4.9 A Quantitative Analysis of Ignition, Propagation and Extinction. 5 Spontaneous Ignition. 5.1 Introduction. 5.2 Theory of Spontaneous Ignition. 5.3 Experimental Methods. 5.4 Time for Spontaneous Ignition. 6 Ignition of Liquids. 6.1 Introduction. 6.2 Flashpoint. 6.3 Dynamics of Evaporation. 6.4 Clausius-Clapeyron Equation. 6.5 Evaporation Rates. 7 Ignition of Solids. 7.1 Introduction. 7.2 Estimate of Ignition Time Components. 7.3 Pure Conduction Model for Ignition. 7.4 Heat Flux in Fire. 7.5 Ignition in Thermally Thin Solids. 7.6 Ignition of a Thermally Thick Solid. 7.7 Ignition Properties of Common Materials. 8 Fire Spread on Surfaces and Through Solid Media. 8.1 Introduction. 8.2 Surface Flame Spread - The Thermally Thin Case. 8.3 Transient Effects. 8.4 Surface Flame Spread for a Thermally Thick Solid. 8.5 Experimental Considerations for Solid Surface Spread. 8.6 Some Fundamental Results for Surface Spread. 8.7 Examples of Other Flame Spread Conditions. 9 Burning Rate. 9.1 Introduction. 9.2 Diffusive Burning of Liquid Fuels. 9.3 Diffusion Flame Variables. 9.4 Convective Burning for Specific Flow Conditions. 9.5 Radiation Effects on Burning. 9.6 Property Values for Burning Rate Calculations. 9.7 Suppression and Extinction of Burning. 9.8 The Burning Rate of Complex Materials. 9.9 Control Volume Alternative to the Theory of Diffusive Burning. 9.10 General Considerations for Extinction Based on Kinetics. 9.10.1 A demonstration of the similarity of extinction in premixed and diffusion flames. 9.11 Applications to Extinction for Diffusive Burning. 10 Fire Plumes. 10.1 Introduction. 10.2 Buoyant Plumes. 10.3 Combusting Plumes. 10.4 Finite Real Fire Effects. 10.5 Transient Aspects of Fire Plumes. 10.5.1 Starting plume. 10.5.2 Fireball or thermal. 11 Compartment Fires. 11.1 Introduction. 11.2 Fluid Dynamics. 11.3 Heat Transfer. 11.4 Fuel Behavior. 11.5 Zone Modeling and Conservation Equations. 11.6 Correlations. 11.7 Semenov Diagrams, Flashover and Instabilities. 12 Scaling and Dimensionless Groups. 12.1 Introduction. 12.2 Approaches for Establishing Dimensionless Groups. 12.3 Dimensionless Groups from the Conservation Equations. 12.4 Examples of Specific Correlations. 12.5 Scale Modeling. Appendix. Flammability Properties. Archibald Tewarson. Index.

Spread of a laminar diffusion flame

Abstract: A theoretical description is presented for a laminar diffusion flame spreading against an air stream over a solid- or liquid-fuel bed. Both a thin sheet and a semi-infinite fuel bed are considered. The burning process is described as follows: The hot flame heats the unburned fuel bed, which subsequently vaporizes. The resulting fuel vapor reacts with the oxygen supplied by the incoming air, thereby producing the heat that maintains the flame-spread process. The formulated model treats the combustion as a diffusion flame, for which the details of the reaction kinetics can be ignored by assuming infinite reaction rates. The model includes the chemical stoichiometry, heat of combustion, gas-phase conductive heat transfer, radiation, mass transfer, fuel vaporization, and fuel-bed thermal properties. The radiation is mathematically treated as a heat loss at the flame sheet and a heat gain at the fuel-bed surface. The calculated flame-spread formulas are not inconsistent with available experimental data. These results reveal much of the physics involved in a spreading, flame. For instance, the flame-spread rate is strongly influenced by (1) the adiabatic stoichiometric flame temperature, and (2) the fuel-bed thermal properties, except for the fuel-bed conductivity parallel to the propagation direction.