Radiation-affected laminar flame quenching

✍ Scribed by Vedat S. Arpaci; Rodney J. Tabaczynski

• Publisher: Elsevier Science
• Year: 1984
• Tongue: English
• Weight: 576 KB
• Volume: 57
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(84)90055-5

✦ Synopsis

Under the influence of radiation, the increase in Peclet number characterizing the flame quench distance A, p.cpSu Tb ° adiabatic flame enthalpy flow Pe---hTb°/A conduction and the decrease in flame temperature are shown in terms of an original radiation number T/T(I -6./2)Bb 0 total radiation I + 3~'2(2/¢. -1)/(1 -o~) adiabatic flame ethalphy flow

where p is the density, cp the specific heat at constant pressure, Su the laminar flame speed, Tb the flame temperature, subscript u the unburned gas and superscript 0 the adiabatic gas, ), the thermal conductivity, 7/= (rp/rR)"2 the weighted nongrayness, rp and rR being the Planck mean and the Rosseland mean of the absorption coefficient, ¢. the wall emissitivity, r= rMI the optical thickness, XM = (rpxR)~/2 being the mean absorption coefficient and I a characteric length (related to geometry or quench distance), o~ the albedo of single scattering, and Bb ° the adiabatic flame Boltzmann number.

4Eb ° emission

Bb0= -p,cpS. °T b° adiabatic flame enthaipy flow

where Eb is the blackbody emissive power.

It is qualitatively shown that the contribution of radiation to the heat transfer and the laminar flame quenching in small diesel engines can be as much as 35%.