Sooting tendencies of primary reference fuels in atmospheric laminar diffusion flames burning into vitiated air

Numerical study of soot formation in laminar coflow methane/air diffusion flames doped by n- heptane/toluene and iso-octane/toluene blends

“…In particular, the focus is on the chemical kinetic interactions between iso-octane and toluene and between nheptane and toluene with respect to PAH and soot formation. This study is complementary to the previous studies [5,19], where soot formation in laminar coflow methane/air diffusion flames doped with iso-octane and n-heptane blends was conducted experimentally and numerically, to gain a more comprehensive understanding of soot formation in diffusion flames fueled with binary mixtures of TRF components.…”

“…The sooting tendency of these binary mixtures was determined by considering the Yield Sooting Indices (YSI) based on n-hexane and benzene. The soot production tendency of PRF was found to increase linearly with the volume fraction of iso-octane [5]. In contrast, the sooting tendency of n-heptane/toluene and iso-octane/toluene mixtures was found to increase in a non-linear and monotonic fashion with the toluene mole fraction [6].…”

“…It should be pointed out that varying the refraction index from 0.28 to 0.308 as X tol varies from 0 to 1 modifies the measurements of soot volume fraction by only about 10 % which significantly less than the experimental uncertainty related to the value of E(m) itself. Further details of the experimental setup and soot measurements using the LEM technique can be found in [5,6].…”

“…The sooting tendencies of gasoline, diesel, jet-A fuels and their surrogates were experimentally investigated in a laminar coflow heated methane/air diffusion flame at atmospheric pressure by doping methane with a small amount of vaporized liquid fuels (2200-2300 ppm) [4]. Kashif et al conducted similar experiments to characterize the fuel sooting propensity of binary mixtures of n-heptane and iso-octane, n-heptane and toluene, and iso-octane and toluene [5,6]. They considered laminar CH 4 /air coflow diffusion flames doped with these vaporized binary mixtures.…”

“…Although it is important to investigate the effects of these factors on soot emissions from GDI engines, it is challenging to isolate the influence of a particular factor, such as fuel chemistry, on soot formation, as the high sensitivity of soot emissions from a GDI engine to various engine parameters can mask the effect of this particular factor on soot formation. In order to circumvent this drawback, well-controlled laminar diffusion flames have been often used [3][4][5][6][7].…”