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Liñán's Flame Speed
In combustion, Liñán's flame speed provides the estimate of the upper limit for edge-flame propagation velocity, when the flame curvature is small. The formula is named after Amable Liñán. When the flame thickness is much smaller than the mixing-layer thickness through which the edge flame is propagating, a flame speed can be defined as the propagating speed of the flame front with respect to a region far ahead of the flame. For small flame curvatures ( flame stretch), each point of the flame front propagates at a laminar planar premixed speed S_L that depends on a local equivalence ratio \phi just ahead of the flame. However, the flame front as a whole do not propagate at a speed S_L since the mixture ahead of the flame front undergoes thermal expansion due to the heating by the flame front, that aids the flame front to propagate faster with respect to the region far ahead from the flame front. Liñán estimated the edge flame speed to be: :\frac \sim \left(\frac\right)^, where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion does not always result in fire, because a flame is only visible when substances undergoing combustion vaporize, but when it does, a flame is a characteristic indicator of the reaction. While activation energy must be supplied to initiate combustion (e.g., using a lit match to light a fire), the heat from a flame may provide enough energy to make the reaction self-sustaining. The study of combustion is known as combustion science. Combustion is often a complicated sequence of elementary reaction, elementary Radical (chemistry), radical reactions. Solid fuels, such as wood and coal, first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies the heat required to produce more of them. Combustion is often hot e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amable Liñán
Amable Liñán Martínez (born 1934 in Noceda de Cabrera, Castrillo de Cabrera, León, Spain) is a Spanish aeronautical engineer working in the field of combustion. Biography He holds a PhD in Aeronautical Engineering from the Technical University of Madrid, advised by Gregorio Millán Barbany and Degree of Aeronautical Engineer from the Caltech advised by Frank E. Marble. He is currently Professor of Fluid Mechanics and professor emeritus at the Higher Technical School of Aeronautical Engineers of the Polytechnic University of Madrid (attached to the Department of Motorcycle and Thermofluidodynamics of said school). He has taught at universities in California, Michigan and Princeton University in the United States and in Marseilles in France, among others. Since 1997 he is an adjunct professor at Yale University. Research He has focused his research studies on the basic problems of combustion, both reactor and planetary probe dynamics, in the latter case working directl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics Of Fluids
''Physics of Fluids'' is a monthly peer-reviewed scientific journal covering fluid dynamics, established by the American Institute of Physics in 1958, and is published by AIP Publishing. The journal focus is the dynamics (physics), dynamics of gases, liquids, and complex or multiphase flow, multiphase fluids—and the journal contains original research resulting from theoretical physics, theoretical, computational fluid dynamics, computational, and experimental physics, experimental studies. History From 1958 through 1988, the journal included plasma (physics), plasma physics. From 1989 until 1993, the journal split into ''Physics of Fluids A'' covering fluid dynamics, and ''Physics of Fluids B,'' on plasma physics. In 1994, the latter was renamed ''Physics of Plasmas'', and the former continued under its original name, ''Physics of Fluids''. The journal was originally published by the American Institute of Physics in cooperation with the American Physical Society's Division of Fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flame Stretch
In combustion, flame stretch (K) is a quantity which measures the amount of stretch of the flame surface due to curvature and due to the outer velocity field strain. The early concept of flame stretch was introduced by Karlovitz in 1953, although the correct definition was introduced by Forman A. Williams in 1975. George H. Markstein studied flame stretch by treating the flame surface as a hydrodynamic discontinuity (known as flame front). The flame stretch is also discussed by Bernard Lewis and Guenther von Elbe in their book. All these discussions treated flame stretch as an effect of flow velocity gradients. The stretch can be found even if there is no velocity gradient, but due to the flame curvature. So, the definition required a more general formulation and its precise definition is given as the ratio of rate of change of flame surface area to the area itself :K = \frac\frac. When K>0, the flame is stretched, otherwise compressed. Sometimes the flame stretch is defined as n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premixed Flame
A premixed flame is a flame formed under certain conditions during the combustion of a premixed charge (also called pre-mixture) of fuel and oxidiser. Since the fuel and oxidiser—the key chemical reactants of combustion—are available throughout a homogeneous stoichiometric premixed charge, the combustion process once initiated sustains itself by way of its own heat release. The majority of the chemical transformation in such a combustion process occurs primarily in a thin interfacial region which separates the unburned and the burned gases. The premixed flame interface propagates through the mixture until the entire charge is depleted. The propagation speed of a premixed flame is known as the flame speed (or burning velocity) which depends on the convection-diffusion-reaction balance within the flame, i.e. on its inner chemical structure. The premixed flame is characterised as laminar or turbulent depending on the velocity distribution in the unburned pre-mixture (which prov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equivalence Ratio
Equivalence or Equivalent may refer to: Arts and entertainment *Album-equivalent unit, a measurement unit in the music industry *Equivalence class (music) *'' Equivalent VIII'', or ''The Bricks'', a minimalist sculpture by Carl Andre *'' Equivalents'', a series of photographs of clouds by Alfred Stieglitz Language *Dynamic and formal equivalence in translation * Equivalence (formal languages) Law *The doctrine of equivalents in patent law *The equivalence principle as if impacts on the direct effect of European Union law Logic *Logical equivalence, where two statements are logically equivalent if they have the same logical content * Material equivalence, a relationship where the truth of either one of the connected statements requires the truth of the other Science and technology Chemistry * Equivalent (chemistry) *Equivalence point *Equivalent weight Computing * Turing equivalence (theory of computation), or Turing completeness *Semantic equivalence in computer metadata E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density
Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be used: \rho = \frac, where ''ρ'' is the density, ''m'' is the mass, and ''V'' is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate this quantity is more specifically called specific weight. For a pure substance, the density is equal to its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium is the densest known element at standard conditions for temperature and pressure. To simplify comparisons of density across different systems of units, it is sometimes replaced by the dimensionless quantity "relative den ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combustion And Flame
''Combustion and Flame'' is a monthly peer-reviewed scientific journal published by Elsevier on behalf of the Combustion Institute. It covers fundamental research on combustion science. The editors-in-chief are Fokion Egolfopoulos (University of Southern California) and Thierry Poinsot (Centre National de la Recherche Scientifique). Abstracting and indexing The journal is abstracted and indexed in: According to the ''Journal Citation Reports'', the journal has a 2020 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 4.185, ranking it 9th out of 60 in the category of ''Thermodynamics''. See also References External links * {{Official website, http://www.journals.elsevier.com/combustion-and-flame Elsevier academic journals Chemistry journals Physics journ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proceedings Of The Combustion Institute
The ''Proceedings of the Combustion Institute'' are the proceedings of the biennial Combustion Symposium put on by The Combustion Institute. The publication contains the most significant contributions in fundamentals and applications, fundamental research of combustion science and combustion phenomena. Research papers and invited topical reviews are included on topics of reaction kinetics, soot, PAH and other large molecules, diagnostics, laminar flames, turbulent flames, heterogenous combustion, spray and droplet combustion, detonations, explosions and supersonic combustion, fire research, stationary combustion systems, internal combustion engine and gas turbine combustion, and new technology concepts. The editors-in-chief are Daniel C. Haworth (Pennsylvania State University) and Terese Løvås ( no) (Norwegian University of Science and Technology). History The need for development of automotive engines, fuels, and aviation formed the basis for the organization which became Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluid Dynamics
In physics, physical chemistry and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids – liquids and gases. It has several subdisciplines, including (the study of air and other gases in motion) and (the study of water and other liquids in motion). Fluid dynamics has a wide range of applications, including calculating forces and moment (physics), moments on aircraft, determining the mass flow rate of petroleum through pipeline transport, pipelines, weather forecasting, predicting weather patterns, understanding nebulae in interstellar space, understanding large scale Geophysical fluid dynamics, geophysical flows involving oceans/atmosphere and Nuclear weapon design, modelling fission weapon detonation. Fluid dynamics offers a systematic structure—which underlies these practical disciplines—that embraces empirical and semi-empirical laws derived from flow measurement and used to solve practical problems. The solution to a fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
