Turbulent forced diffusion flames

✍ Scribed by Vedat S. Arpaci; C.Y. Li

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 601 KB
• Volume: 102
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(95)00026-3

✦ Synopsis

A microscale, % -0jj"3, is introduced for turbulent diffusion flames, where t) and me, respectively, are the Kolmogorov scale and the flame Schmidt number. In terms of this scale, the turbulent mass transfer integrated over a length I of a liquid fuel is shown to be M' = pBL, % where p is the dynamic viscosity and B is the transfer number, B = (yOmQ/~oMo -h,)/hfg, where Y. is the mass fraction of oxidizer, Yo, its ambient value, Q the heat release for a simple global chemical reaction, and v. and Mo the oxidant stoichiometric coefficient and molecular weight, respectively, h, = c,(T, -T,), cP the specific heat of gas, 7" and T, the fuel and ambient temperatures, respectively, and hfg the heat of evaporation. It is shown by the similarity between the mass and momentum transfer, M' -_=C /LB f' C, being the drag coefficient, and that M'/@ Cf 1 (M'//LB)~=~ = ___ = (cf)B=o (1 + B)3'4 '

where the subscriot B = 0 for the case without boundary mass transfer. The agreement between the mode1 and the sparse experimental data is reasonable.