Comparative analysis of soot formation processes of diesel and ABE (Acetone-Butanol-Ethanol) based on CFD coupling with phenomenological soot model

The improved nine-step phenomenological soot model of diesel and ten-step phenomenological soot model of ABE (Acetone-Butanol-Ethanol) which had been confirmed in previous studies were implemented into KIVA-3V Release 2 code, and then multi-dimensional computational fluid dynamics (CFD) simulations were conducted to investigate the combustion characteristics and soot formation process of diesel and ABE in constant volume chamber at different temperatures (800 K and 1000 K) and oxygen concentrations (21% and 16%). The comparative results of their soot formation processes and intermediate products indicate that, in the combustion process, the soot mass of ABE and diesel presents in the form of parabolic curve with time change, the soot generation tendency of ABE is lower than diesel, and the initial temperature and oxygen concentration have little effect on the relative relations of their soot and intermediate products mass. At the oxygen concentration of 21%, when initial temperature decreases from 1000 K to 800 K, the soot mass peak values of diesel and ABE reduce by 40% and 83%, respectively. At the initial temperature of 800 K, the relative relations of their soot number and OH free radical keep unchanged; nevertheless, the mass of ABE's C2H2 and precursor exceeds that of diesel's in the early stage of combustion. At the initial temperature of 1000 K, when oxygen concentration decreases from 21% to 16%, the soot mass peak values of diesel and ABE increase by 20% and 25%, respectively. At the same time, the C2H2, precursor and soot number increase in diesel but decrease in ABE. (C) 2017 Elsevier Ltd. All rights reserved.