Laminar Burning Velocities of 2,5-Dimethylfuran Compared with Ethanol and Gasoline

Abstract

The 2,5-dimethylfuran (DMF) has attracted renewed global interest since its improved production methods were published in Nature and Science in 2007. Its high energy density makes it a promising biofuel and a possible alternative to gasoline. Consequently, a series of studies, led by the University of Birmingham, aims to assess the potential of DMF as an automotive energy carrier. These studies will include an analysis of the spray properties, the laminar flame characteristics, the engine performance, and the subsequent emissions. This paper examines the laminar flame characteristics from a quiescent homogeneous air−fuel mixture. The experiments were conducted using a constant volume vessel and were recorded by high speed schlieren visualization. By measurement of the flame growth following ignition, the laminar flame speed was determined. The calculation of flame stretch yielded the Markstein lengths and the laminar burning velocities. This paper presents the results of DMF combustion for a range of equivalence ratios (0.6−2.0) and initial temperatures (50−100 °C). The flame performance when using DMF is compared to EN228 gasoline and to the most commonly used biofuel substitute for gasoline, ethanol. The data shows that ethanol has the highest laminar burning velocity, followed by gasoline, and then DMF. In the 0.9−1.1 equivalence ratio range, the laminar burning velocity of DMF was very similar to gasoline and the difference was within 10%.

Effect of injection timing on mixture formation and combustion in an ethanol direct injection plus gasoline port injection (EDI+GPI) engine

“…The ECFM combustion model was properly tuned by acting on the intermediate turbulent net flame stretch (ITNFS) term so that the modelled in-cylinder pressure traces matched the experimental data. The laminar flame speeds of ethanol and gasoline fuels were taken from the experiments [53]. The turbulent flame speed was calculated based on the laminar flame speed and the local turbulence intensity in the combustion model.…”

“…The flame speed and combustion temperature reach their peaks at the stoichiometric equivalence ratio. Either lean or rich mixture results in much lower combustion speed and temperature [53,56]. Consequently, as shown in Fig.…”

“…10, the ethanol droplets evaporate and lead to very rich mixture in the high concentration regions. When the equivalence ratio is higher than 2.0, the flame speed becomes very slow [53]. Secondly, the over-cooling effect becomes significant with late EDI injections.…”

Experimental Investigation on the Laminar Burning Velocities and Markstein Lengths of Methane and PRF95 Dual Fuels

“…A common approach of measuring burning velocity and Markstein length in a combustion vessel has been the constant pressure outwardly propagating spherical flame method (10)(11)(12)(13)(14)(15)(16)18,19). The method is suitable for extrapolation of measured stretched burning velocities to their fundamental non-stretched values and the associate Markstein lengths, due to the welldefined stretch rates of an outwardly spherical flame.…”

“…The light was focused onto a slit using a focusing lens in order to generate the spotlight for the schlieren technique. Passing through a group of mirrors, the light path was then cut by a knife-edge which is essential for the schlieren method (10). Two different high speed cameras have been used for the current experimental work.…”