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Bray–Moss–Libby Model
In premixed turbulent combustion, Bray–Moss–Libby (BML) model is a closure model for a scalar field, built on the assumption that the reaction sheet is infinitely thin compared with the turbulent scales, so that the scalar can be found either at the state of burnt gas or unburnt gas. The model is named after Kenneth Bray, J. B. Moss and Paul A. Libby. Mathematical description Let us define a non-dimensional scalar variable or progress variable c such that c=0 at the unburnt mixture and c=1 at the burnt gas side. For example, if T_u is the unburnt gas temperature and T_b is the burnt gas temperature, then the non-dimensional temperature can be defined as :c=\frac. The progress variable could be any scalar, i.e., we could have chosen the concentration of a reactant as a progress variable. Since the reaction sheet is infinitely thin, at any point in the flow field, we can find the value of c to be either unity or zero. The transition from zero to unity occurs instantaneously a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kenneth Bray
Kenneth Noel Corbett Bray FRS is emeritus professor at University of Cambridge. Life He was editor of ''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 ...'' from 1981 to 1986. Works"Studies of the Turbulent Burning Velocity" K. N. C. Bray, ''Proceedings: Mathematical and Physical Sciences'', Vol. 431, No. 1882 (8 November 1990), pp. 315–335 * References External links {{DEFAULTSORT:Bray, Kenneth English mechanical engineers Engineering professors at the University of Cambridge Fellows of the Royal Society Living people Fellows of the Combustion Institute Year of birth missing (living people) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul A
Paul may refer to: People * Paul (given name), a given name, including a list of people * Paul (surname), a list of people * Paul the Apostle, an apostle who wrote many of the books of the New Testament * Ray Hildebrand, half of the singing duo Paul & Paula * Paul Stookey, one-third of the folk music trio Peter, Paul and Mary * Billy Paul, stage name of American soul singer Paul Williams (1934–2016) * Vinnie Paul, drummer for American Metal band Pantera * Paul Avril, pseudonym of Édouard-Henri Avril (1849–1928), French painter and commercial artist * Paul, pen name under which Walter Scott wrote ''Paul's letters to his Kinsfolk'' in 1816 * Jean Paul, pen name of Johann Paul Friedrich Richter (1763–1825), German Romantic writer Places * Paul, Cornwall, a village in the civil parish of Penzance, United Kingdom *Paul (civil parish), Cornwall, United Kingdom * Paul, Alabama, United States, an unincorporated community * Paul, Idaho, United States, a city * Paul, Nebraska, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dirac Delta Function
In mathematical analysis, the Dirac delta function (or distribution), also known as the unit impulse, is a generalized function on the real numbers, whose value is zero everywhere except at zero, and whose integral over the entire real line is equal to one. Thus it can be Heuristic, represented heuristically as \delta (x) = \begin 0, & x \neq 0 \\ , & x = 0 \end such that \int_^ \delta(x) dx=1. Since there is no function having this property, modelling the delta "function" rigorously involves the use of limit (mathematics), limits or, as is common in mathematics, measure theory and the theory of distribution (mathematics), distributions. The delta function was introduced by physicist Paul Dirac, and has since been applied routinely in physics and engineering to model point masses and instantaneous impulses. It is called the delta function because it is a continuous analogue of the Kronecker delta function, which is usually defined on a discrete domain and takes values ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Release Parameter
In combustion, heat release parameter (or gas expansion parameter) is a dimensionless parameter which measures the amount of heat released by an adiabatic combustion process. It is defined as :q = \frac where *T_ is the adiabatic flame temperature *T_u is the unburnt mixture temperature. In typical combustion process, q\approx 2-7. For isobaric combustion, using ideal gas law, the parameter can be expressed in terms of 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 u ...,Clavin, P. (1985). Dynamic behavior of premixed flame fronts in laminar and turbulent flows. Progress in energy and combustion science, 11(1), 1-59. i.e., :q = \frac = \frac. The ratio of burnt gas to unburnt gas temperature is :\frac =1+q. Gas expansion ratio The gas expansion ratio is simply defined by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Favre Averaging
Favre averaging is the density-weighted averaging method, used in variable density or compressible turbulent flows, in place of the Reynolds averaging. The method was introduced formally by the French physicist Alexandre Favre in 1965, although Osborne Reynolds Osborne Reynolds (23 August 1842 – 21 February 1912) was an Irish-born British innovator in the understanding of fluid dynamics. Separately, his studies of heat transfer between solids and fluids brought improvements in boiler and condenser ... had also already introduced the density-weighted averaging in 1895. The averaging results in a simplistic form for the nonlinear convective terms of the Navier-Stokes equations, at the expense of making the diffusion terms complicated. Favre averaged variables Favre averaging is carried out for all dynamical variables except the pressure. For the velocity components, u_i, the Favre averaging is defined as: \widetilde= \frac, where the overbar indicates the typical Reynolds ... [...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] |
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] |
