Measurements of Laminar Burning Velocities and Markstein Lengths ofn-Butanol−Air Premixed Mixtures at Elevated Temperatures and Pressures

Abstract

Measurements of laminar burning velocities and Markstein lengths of n-butanol-air premixed mixtures was made over a wide range of equivalence ratios at initial temperatures of 413, 443, and 473 K and initial pressures of 0.1 and 0.25 MPa using the high-speed schlieren photography and outwardly propagating flame. Effects of laminar flame thickness, thermal expansion ratio, and flame Lewis number on flame stability response were studied. Schlieren photos of flame propagation are recorded. The results show that laminar burning velocities of n-butanol-air premixed mixtures are increased with the increase of initial temperature, and they decrease with the increase of initial pressure. Markstein lengths are decreased with the increase of the equivalence ratio, and they decrease with the increase of initial temperature, and all these indicate that the flame instability is increased with the increase of equivalence ratio, the decrease of initial pressure, and the increase of initial temperature.

Characterisation of flame development with ethanol, butanol, iso-octane, gasoline and methane in a direct-injection spark-ignition engine

“…The laminar burning velocity has been measured for a range of hydrocarbon and alcohol fuels for various conditions by Gülder [20,21], Metghalchi and Keck [22] and Bradley et al [23] among others. More recently, results have been reported by Gu et al [24] for methane, by Liao et al [25] and Bradley et al [26] for ethanol, by Al-Shahrany et al [27] for iso-octane, by Jerzembeck et al [28] for gasoline, by Gu et al [29] and Sarathy et al [30] for butanol, and by Beeckmann et al [31,32] for most of these fuels. A large database of fuel structure effects was also produced by Farrell et al [33]; these authors reported data derived from thermodynamic analysis of the pressure rise from explosions in a combustion vessel (typically at 3 bar, 450 K), following the approach of Metghalchi and Keck [22].…”

“…However, the differences between [34] and [22] were very small around stoichiometry for iso-octane at engine-like conditions, as can be seen in Table 4; nevertheless, the data of [34] confirm iso-octane's marginally lower laminar burning velocity at engine-like conditions than ethanol's (of the order 1 cm/s). Butanol laminar velocity data have only very recently become available [29][30][31][32]43]; these have reported ~10% lower values than ethanol at atmospheric pressure but very similar or marginally higher values at higher pressures for the same temperatures. Specifically, Gu et al [29,43] reported values of laminar burning velocity between 0.45-0.5 m/s for similar temperatures to those at ignition timing of the current study.…”

“…Butanol laminar velocity data have only very recently become available [29][30][31][32]43]; these have reported ~10% lower values than ethanol at atmospheric pressure but very similar or marginally higher values at higher pressures for the same temperatures. Specifically, Gu et al [29,43] reported values of laminar burning velocity between 0.45-0.5 m/s for similar temperatures to those at ignition timing of the current study.…”

An analysis of spray development with iso-octane, n-pentane, gasoline, ethanol and n-butanol from a multi-hole injector under hot fuel conditions

“…Ethanol boils at 78.4 °C and n-Butanol at 117 °C at atmospheric pressure. It should be noted here that n-Butanol (1-Butanol) was selected for this study instead of its isomer iso-Butanol because of the existence of some data on laminar burning velocity for this fuel that could assist parallel analysis of engine combustion data in direct comparison to the other fuels [11][12][13]. However, iso-Butanol is currently also being studied and results will be discussed in future publications (some laminar burning velocity data for Butanol's isomers have also been recently published [14]).…”

Flame front analysis of ethanol, butanol, iso-octane and gasoline in a spark-ignition engine using laser tomography and integral length scale measurements

“…[82,83] According to this, iso-octane would have best stabilising capabilities against thermo-diffusive instabilities, and 7% lower for gasoline (6.18 m/s). The higher velocities at the crests, i.e.…”