The implications of the probability equations for turbulent combustion models

摘要: Abstract The physical foundations of combustion models employed in turbulent flow calculation procedures are examined by reference to the transport equation for joint probability distribution scalars characterizing system. It is shown that, with certain restrictions, an arbitrarily fuelled flame resulting from a one-step irreversible reaction can be characterized two scalars, total fuel mass fraction, f , and fraction products, c . This system includes special cases premixed diffusion flames. introduced discussed: it limit very rapid reaction, expressed terms single distributions scalar, A which represents activated species. By deriving equations these quantities modelling unknown closure obtained used assess existing models. Lockwood Naguib's [9] model flames derived [6, 7] sound principle but improvements detail indicated. An alternative provided eddy-break-up [1] found deficient on mathematical grounds.