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Show The mean density is obtained from the equation of state for a perfect gas : K p = PRTY^(Yk/Mk) (2) fc=i where p is the pressure, R the universal gas constant, p the density, T the temperature, Yk the mass fraction of species k, M k the molecular weight of species k. 4> l u, h Yf* k £ Sf 1 e 0 Me Me/crh Me/<7/u Me Me/<7£ Me/^S, k-e model constants s+ 0 dp (du. du, \ 2 / dui. \ 0 ^/u = -p2ULSf Pk- pi (CuPk-C2ePt)^ k >^y)&>-^> *-Ke+Sf)-M-S+'0] du{ Cl€-=1.44, C 2 e = 1.92, CM=0.09, <rk=l, <re=1.3, crh=0.7, (7^=0.7, crSf=l Table 1 Definitions of exchange coefficient Tf and source term S COMBUSTION MODEL Background Originally developed by Marble and Broadwell [12] for non premixed flames, the Coherent Flame Model (CFM) describes the turbulent reaction field as a collection of laminar flame elements. These elements are convected and distorted by the turbulent motion but retain an identifiable structure (the flamelets remain 'coherent', i.e. 'organized'). The F S D description has been extended to premixed flow configurations by Candel et al. [6]. The flame surface density (FSD) balance equation takes into account ttansport, diffusion, production and destruction of flame area, and it is cast in the following general form : {transport} = {turbulent diffusion) + {production} - {destruction}. Initially devised on the basis of some intuitive arguments, the balance equation of flame surface is actually derived 3 |