作者: William B Bush , Francis E Fendell
DOI: 10.1016/0094-5765(74)90026-5
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摘要: Abstract For control and safety, combustion in engineering devices often concerns the burning of highly reactive, initially unmixed fuel oxidant. The rate-controlling step is then mixing reactants; further, turbulent known to be more rapid than laminar mixing. Thus, diffusion flames shear flows arise a wide variety problems, including propulsion continuous chemical lasers. Toor has suggested method by which time-averaged solutions for passive scalars with Lewis-Semenov number unity can used obtain reactant mass fractions temperature flames. This analogue that Burke Schumann, who have shown how convection-diffusion inert species Toor's does require knowledge probability distribution function states available fluctuating portion involved. Because many lasers are operated mixing-rate-controlled combustion, because finite-rate reactions necessitate adoption speculative closures law action, frozen equilibrium limits taken bound behaviors unpremixed systems, there motivation implement Toor. Closure schemes layers should permit analytic prediction required mean fields scalars. Although these boundary-value problems usually solved numerically, recently, multiple-scaling techniques been employed successfully limit large Reynolds display important properties solutions. While experiment necessary determination functions, arguments made functions depart significantly from frequently assumed Gaussian-type forms, so predictions based on such normal distributions dubious accuracy.