Laminar flame speeds of C5 to C8 n-alkanes at elevated pressures: Experimental determination, fuel similarity, and stretch sensitivity

Kelley, Andrew; Smallbone, Andrew; Zhu, Daniel; Law, Chung K.

doi:10.1016/j.proci.2010.06.074

Cited by 140 publications

(68 citation statements)

References 20 publications

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“…N -heptane is used as the fuel in all simulations (in place of n-hexane) since the chemistry of n-heptane is better understood than that of n-hexane. This decision is justified by previous studies which have shown that normal alkanes show very similar ignition and flame propagation characteristics (Davis & Law 1998b;Shen et al 2009;Westbrook et al 2009;Kelley et al 2011).…”

Section: Reaction Mechanismmentioning

confidence: 86%

“…To assess the accuracy of the chemistry representation, the detailed reaction mechanism is used to estimate flame speeds for n-heptane/air mixtures at different equivalence ratios and unburned gas temperatures at which experimental data are available from the literature (Davis & Law 1998a;Huang, Sung & Eng 2004;Kumar et al 2007;Ji et al 2010;Kelley et al 2011;Van Lipzig et al 2011). The agreement between experiments and simulations is excellent for lean and stoichiometric mixtures as shown in figure 2(a).…”

Section: Reaction Mechanismmentioning

confidence: 99%

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Cyclic flame propagation in premixed combustion

et al. 2013

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In experiments of hot surface ignition and subsequent flame propagation, a puffing flame instability is observed in mixtures that are stagnant and premixed prior to ignition. By varying the size of the hot surface, power input, and combustion vessel volume, it was determined that the instability is a function of the interaction of the flame, with the fluid flow induced by the combustion products rather than the initial plume established by the hot surface. Pressure ranges from 25 to 100 kPa and mixtures of n-hexane/air with equivalence ratios between φ = 0.58 and 3.0 at room temperature were investigated. Equivalence ratios between φ = 2.15 and 2.5 exhibited multiple flame and equivalence ratios above φ = 2.5 resulted in puffing flames at atmospheric pressure. The phenomenon is accurately reproduced in numerical simulations and a detailed flow field analysis revealed competition between the inflow velocity at the base of the flame and the flame propagation speed. The increasing inflow velocity, which exceeds the flame propagation speed, is ultimately responsible for creating a puff. The puff is then accelerated upward, allowing for the creation of the subsequent instabilities. The frequency of the puff is proportional to the gravitational acceleration and inversely proportional to the flame speed. A scaling relationship describes the dependence of the frequency on gravitational acceleration, hot surface diameter, and flame speed. This relation shows good agreement for rich n-hexane/air and lean hydrogen/air flames, as well as lean hexane/hydrogen/air mixtures.

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Section: Reaction Mechanismmentioning

confidence: 86%

Section: Reaction Mechanismmentioning

confidence: 99%

Cyclic flame propagation in premixed combustion

et al. 2013

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“…The agreement between the measurements of the two studies was overall good, albeit current measurements were consistently higher compared to corresponding u l values in [5,8]. Maximum differences of up to 10% between the two studies were found for lean (φ = 0.8) n-pentane and rich (φ = 1.1) n-octane.…”

Section: Laminar Burning Velocitymentioning

confidence: 59%

“…Measurements of their laminar burning velocity have been performed by a number of previous workers at a range of conditions [2,4,[8][9]. Apart from the size of the carbon chain, which affects the number of breakdown steps needed during oxidation, another significant difference anticipated to have impact on burn rate, is the differing molar mass of the fuels selected for this study and, thus, their differing Lewis Number (or Markstein Number).…”

Section: Introductionmentioning

confidence: 99%

Turbulent burning rates of gasoline components, Part 2 – Effect of carbon number

Burluka

Gaughan

Griffiths

et al. 2016

Fuel

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Experimental measurements of turbulent and laminar burning velocities have been made for premixed hydrocarbon-air flames of straight chain molecules of increasing carbon number (from n-pentane to n-octane). Measurements were performed at 0.5 MPa, 360 K and rms turbulent velocities of 2 and 6 m/s, for a range of equivalence ratios. The laminar burning velocities were used to interpret the turbulent data, but were also found to be broadly in line with those of previous workers. At lean conditions the turbulent burning velocity was measured to be similar between the four alkanes studied. However, at rich conditions there were notable differences between the turbulent burn rates of the fuels. The equivalence ratio of the mixtures at which the maximum burning velocities occurred in the turbulent flames was richer than that under laminar conditions. The equivalence ratio of the peak turbulent burning velocity was found to be a function of the carbon number of the fuel and the turbulent intensity and became gradually fuel rich with increases in each of these values.

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“…Temperature and pressure ranged between 1030 and 1380 K and between 1.14 and 6.69 MPa. The laminar burning speed of hexane-air mixtures was investigated by Davis and Law [6], Farell et al [7], Kelley et al [8] and Ji et al [9] using both the counterflow burner and the spherical expanding flame techniques. After surveying this data, the need emerged to obtain some experimental data in the low temperature range in order to evaluate the effectiveness of catalysts in this regime.…”

Section: Introductionmentioning

confidence: 99%

Low temperature oxidation of n-hexane in a flow reactor

Mével

Chatelain

Boettcher

et al. 2014

Fuel

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The risk of igniting a flammable mixture in fuel tank vapor space is a major concern in aviation safety. In order to analyze the hazards and develop mitigation strategies, it is necessary to characterize the explosive properties of kerosene vapor-air mixtures over wide ranges of initial conditions. n-Hexane has been extensively used in our laboratory as a single component surrogate of kerosene. In the present study, hexane oxidation by oxygen was studied in a flow reactor at equivalence ratios of 0.7, 1 and 1.5 for mixtures diluted at 90% with nitrogen. Residence time was set at 2 s and the pressure at 100 kPa. The evolution of the gas phase composition at the reactor exit was studied over the range 450-1000 K. Laser-based diagnostics and gas chromatography analysis were used to characterize the exit mixture composition. The chemical species measurements revealed three distinct regimes of oxidation, namely (i) the cool flame region from 600 to 650 K, (ii) the NTC region between 675 and 775 K, and (iii) the high temperature oxidation regime from 800 K. The modeling study demonstrated the capability of reproducing most of the trends observed

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Laminar flame speeds of C5 to C8 n-alkanes at elevated pressures: Experimental determination, fuel similarity, and stretch sensitivity

Cited by 140 publications

References 20 publications

Cyclic flame propagation in premixed combustion

Cyclic flame propagation in premixed combustion

Turbulent burning rates of gasoline components, Part 2 – Effect of carbon number

Low temperature oxidation of n-hexane in a flow reactor

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