Kinetic Modeling Study on the Combustion Characterization of Synthetic C3 and C4 Alcohols for Lean Premixed Prevaporized Combustion

Abstract

To reach sustainable aviation, one approach is to use electro-fuels (e-fuels) within the gas turbine engines. E-fuels are CO2-neutral synthetic fuels which are produced employing electrical energy generated from renewable resources, where the carbon is taken out of the atmosphere or from biomass. Our approach is, to find e-fuels, which can be utilized in the lean premixed prevaporized (LPP) combustion, where most of the non-CO2 emissions are prevented. One of the suitable e-fuel classes is alcohols with a low number of carbons. In this work, the autoignition properties of propanol isomers and butanol isomers as e-fuels were investigated in a high-pressure shock tube (HPST) at temperatures from 1200 to 1500 K, the pressure of 10 bar, and lean fuel-air conditions. Additional investigations on the low-temperature oxidation and flame speed of C3 and C4 alcohols from the literature were employed to develop a comprehensive mechanism for the prediction of ignition delay time (IDT) and laminar burning velocity (LBV) of the above-mentioned fuels. A numerical model based on newly developed chemical kinetics was applied to further study the IDT and LBV of fuels in comparison to the Jet-A surrogate at the engine-related conditions along with the emissions prediction of the model at lean fuel-air conditions.

Validation of a Generic Non-Swirled Multi-Fuel Burner for the Measurement of Flame Stability Limits for Research of Advanced Sustainable Aviation Fuels

“…With regard to self-ignition delay times, short alcohols can be seen as interesting candidates for such advanced, sustainable aviation fuels. Both experimental and numerical studies conducted by our collaborative research group at PTB Braunschweig indicate that ignition delay times under relevant aviation conditions (assuming 860 K, 36 bar, and a stoichiometric ratio of Φ = 0.75) can be more than an order of magnitude longer compared to Jet A [14]. Simulations of Jet A performed with the mechanism of Honnet et al [15] suggest a 15 to 25 times longer ignition delay for methanol, with a decreasing trend observed for ethanol and propanol (10 to 20 times longer) performed with Nadiri et al [14].…”

“…Both experimental and numerical studies conducted by our collaborative research group at PTB Braunschweig indicate that ignition delay times under relevant aviation conditions (assuming 860 K, 36 bar, and a stoichiometric ratio of Φ = 0.75) can be more than an order of magnitude longer compared to Jet A [14]. Simulations of Jet A performed with the mechanism of Honnet et al [15] suggest a 15 to 25 times longer ignition delay for methanol, with a decreasing trend observed for ethanol and propanol (10 to 20 times longer) performed with Nadiri et al [14]. Additionally, fuels from the furan class were explored (e.g., 2,5-dimethylfuran = DMF, with ignition delay times 10 to 20 times longer), although high fuel prices limited further consideration in advanced experiments.…”

“…The propanol and butanol class of alcohols, with specific energies of 30.8 and 32.9 MJ kg −1 , respectively, emerged as particularly promising for potential future advanced aviation fuels. Comprehensive investigations, including the determination of laminar flame speeds, were conducted for these isomers [14,16].…”