Simulation analysis of soot formation and laminar combustion characteristics of 2,5-dimethylfuran/air at different initial pressures and temperatures

Abstract

In this research, we studied the soot formation and laminar combustion characteristics of 2,5-dimethylfuran (25DMF) at different initial temperatures and initial pressures, and conducted reactive force field molecular dynamics (ReaxFF MD) simulation and dynamical simulation method with a one-dimensional laminar combustion model through CHEMKIN's PREMIXED Code. The full process of soot formation during 25DMF combustion was revealed by ReaxFF MD simulation. There are three stages from the formation of the initial ring, the growth of polycyclic aromatic hydrocarbons (PAHs) and the formation and growth of the initial soot. The growth mechanism of polycyclic aromatic hydrocarbons was mainly divided into 4 types, which were hydrogen-abstraction-C2H2-addition (HACA), carbon-addition-hydrogen-migration (CAHM), clustering of hydrocarbons by radical-chain reactions (CHRCR) mechanism and internal ring formation. For the dynamical model of 25DMF combustion, the initial temperatures (Tu) were set to 298 K, 358 K, 393 K and 423 K, and the initial pressures (pu) were set to 1 atm, 3 atm, 5 atm and 10 atm. The results showed that the laminar burning velocities (LBVs) increased along with the increase of the initial temperature. The LBVs decreased with the increase of initial pressure. Both the increase of the initial temperature and pressure led to a decrease in flame thickness. Studies on soot precursors showed that C2H2, i-C4H5, C4H2, and C6H6 shift upstream in peak molar fraction with increasing initial pressure. C4H2 and C6H6 moved downstream first, then upstream and finally downstream with the increase of initial temperature. C2H2 and i-C4H5 shifted upstream and then downstream with increasing initial temperature.