Laminar Flame Speeds of Gasoline Surrogates Measured with the Flat Flame Method

Abstract

The adiabatic, laminar flame speeds of gasoline surrogates at atmospheric pressure over a range of equivalence ratios of Φ = 0.8–1.3 and unburned gas temperatures of 298–400 K are measured with the flat flame method, which produces a one-dimensional flat flame free of stretch. Surrogates used in the current work are the primary reference fuels (PRFs, mixtures of n-heptane and isooctane), the toluene reference fuels (TRFs, mixtures of toluene and PRFs), and the ethanol reference fuels (ERFs, mixtures of ethanol and PRFs). In general, there is good agreement between the present work and the literature data for single-component fuel and PRF mixtures. Surrogates of TRF mixtures are found to exhibit comparable flame speeds to a real gasoline, while there is discrepancy observed between isooctane and gasoline. Moreover, the laminar flame speeds of TRF mixtures with similar fractions of n-heptane are found to be insensitive to the quantity of toluene in the mixture. Mixtures of ERFs exhibit comparable flame speeds to those of TRFs with similar mole fractions of n-heptane and isooctane.

Exploring gasoline oxidation chemistry in jet stirred reactors

“…Considerable work has been done on studying oxidation of gasoline surrogates and real gasoline fuels [1]. Ignition delay times have been measured for binary primary reference fuels (PRF) [21][22][23][24][25][26], ternary primary reference fuels (TPRF) [31,32], and multi-component surrogates [34][35][36], while flame speeds have been measured for PRFs [27][28][29][30] and TPRFs [33]. Recently [37].…”

Monte-Carlo based laminar flame speed correlation for gasoline

“…In a wider range of conditions, Liao et al [16] has also measured LFS for PRFs and toluene reference fuel (TRFs) in addition to specified surrogates at atmospheric pressure and temperatures up to 400 K. PRFs are binary mixtures of n-heptane and iso-octane whereas TRFs are ternary mixtures of toluene, n-heptane and iso-octane. Mannaa et al [17] investigated the pressure dependence of FACE-C gasoline at 358 K and pressures ranging from 1 bar to 6 bar.…”

“…It is based on the same power-law correlation but by assuming second-order polynomial dependence, as seen in Eqs. (14)(15)(16).…”

“…(17)(18)(19)(20)(21) where the coefficients are given in Table 4. The fitting procedure is described in detail in Appendix C. Figure 11: Comparison between the predicted and expected LFS values, on the left using Equation 1, and on the right using Equation (16), green lines are ±5 cm/s.…”

Gasoline flame behavior at elevated temperature and pressure

“…tures and the published S L measurements for these mixtures are typically available for temperatures ranging from 298 to 400 K at atmospheric pressure[34]. Thus, further measurements at elevated pressures of interest for future engines are required.Two commonly used flame speed correlations are also shown inFig.…”