Spray and combustion characterizations of ABE/Dodecane blend in comparison to alcohol/Dodecane blends at high-pressure and high-temperature conditions

Abstract

This paper presents the spray and combustion characterization of Acetone-Butanol-Ethanol mixture and alcohol fuels, blended with n-Dodecane at different volume ratio, as 20% Acetone-Butanol-Ethanol (ABE20), 20% Butanol (Bu20), 40% Butanol (Bu40), 20% Ethanol (Eth20), as well as 20% Butanol/20% Ethanol (Bu20Eth20) to evaluate the impact of the physical and chemical characteristics, especially fuel oxygen contents. The experiments were carried out in “New One Shot Engine” at high-pressure and high-temperature conditions, established as Spray A condition, defined by Engine Combustion Network (ECN): 60 bar ambient pressure, 22.8 kg/m3 ambient density and various ambient temperatures (800, 850, and 900 K). The liquid and vapor spray parameters were characterized by diffused-back illumination and Schlieren techniques in non-reactive condition (in pure nitrogen). In reactive conditions (with 15% oxygen), the lift-off length and absolute ignition delay were measured by OH∗ chemiluminescence.First, as expected because of slight difference in fuel density, mass flow rates, vapor spray penetration, and spray angle are almost similar. But, due to the highest volatility, the liquid length of ABE20 is shorter compared to pure n-Dodecane and other blends. Also its ignition delay and lift-off length are shorter than those of alcohol blends due to difference in expected cetane number and latent heat of vaporization. The increase of butanol quantity or the addition of ethanol in blends increase the liquid length due to the cooling effect from the latent heat of vaporization, while the lift-off length and ignition delay increase with oxygen contents. Finally, ABE20 seems to be a good candidate for diesel-blended fuel due to the similar behavior as n-Dodecane itself.