Kinetic modelling of extinction and autoignition of condensed hydrocarbon fuels in non-premixed flows with comparison to experiment

Experimental investigations of the influence of pressure on critical extinction conditions of laminar nonpremixed flames burning condensed hydrocarbon fuels, jet fuels, and surrogates

“…The particular value of Y O 2 ;2 ¼ 0:175 is selected because it permits experimental data for a wide range of strain rates and pressures for which the flame is stable and measurable for the fuels tested in the experiment. The ordering of extinction strain rates at elevated pressures is consistent with earlier results of Grana et al [22] for extinction strain rates measured and computed at atmospheric pressures. The highest extinction strain rates were observed for n-heptane, followed by cyclohexane, n-octane and iso-octane, with ndecane having the lowest extinction strain rates.…”

“…This figure shows a significant disagreement for the Aachen surrogate at elevated pressures, but relatively close agreement between the Princeton surrogate and the two jet fuels, with small deviations appearing at pressures above 0.3 MPa. For the Aachen surrogate, rather than closely following the extinction curve of the jet fuels as was observed at atmospheric pressure [22], it followed with little deviation the curve measured for n-decane at elevated pressures, which had significantly higher extinction strain rates than the jet fuels. Figure 5 shows a photograph of surrogate B (2nd generation POSF 4658 Princeton surrogate) side by side with a photograph of JP-8.…”

“…In the condensed fuel configuration a gaseous oxidizing stream flows over the vaporizing surface of a liquid fuel. This configuration was employed in many previous studies at 1 atm [18][19][20][21][22], and at moderate pressures [1,2]. This configuration is employed in the present work.…”

“…In this configuration, a steady axisymmetric, laminar, stagnation-point flow of an oxidizer is directed onto the vaporizing surface of a liquid fuel. This configuration allows for the experimental testing of fuels with high boiling points for which it is difficult to avoid pyrolysis reactions during fuel vaporization [22]. Figure 1 shows a schematic illustration of the basic configuration used.…”

Study of the low-temperature reactivity of large n-alkanes through cool diffusion flame extinction

“…Because of this decoupling, it is possible that chemical kinetic models derived from these zero-dimensional experiments may competently reproduce homogeneous reactor speciation data but at the same time struggle to predict phenomena such as flame speeds, which are strongly affected by the coupling between chemistry, transport, and heat release. To address this issue, complementary experiments including measurements of laminar flame speed [61][62][63][64][65] and counterflow flame extinction [62,63,[66][67][68] are often relied upon to provide the necessary information about heat release and flame behavior in full-strength mixtures. However, these experiments have been widely limited to high-temperature flames.…”