Investigating the Effects of Chemical Mechanism on Soot Formation Under High-Pressure Fuel Pyrolysis

Abstract

We performed Computational Fluid Dynamics (CFD) simulations using a Reynolds-Averaged Navier-Stokes (RANS) turbulence model of high-pressure spray pyrolysis with a detailed chemical kinetic mechanism encompassing pyrolysis of n-dodecane and formation of polycyclic aromatic hydrocarbons. We compare the results using the detailed mechanism and those found using several different reduced chemical mechanisms to experiments carried out in an optically accessible, high-pressure, constant-volume combustion chamber. Three different soot models implemented in the CONVERGE CFD software are used: an empirical soot model, a method of moments, and a discrete sectional method. There is a large variation in the prediction of the soot between different combinations of chemical mechanisms and soot model. Furthermore, the amount of soot produced from all models is substantially less than experimental measurements. All of this indicates that there is still substantial work that needs to be done to arrive at simulations that can be relied on to accurately predict soot formation.

A review of the mineralogical and chemical composition of nanoparticles associated with coal fires

“…Typical soot aggregate with fracture‐like chain structures can extend to a couple of micrometers or more. Individual nano‐size spherules are predominantly composed of black C with minor organic C. They are products of incomplete combustion, occur predominantly in aged smoke, and form through evaporation‐condensation processes (Chakrabarty et al., 2014; Killingsworth et al., 2021; Pósfai et al., 2003; Stanek & Brown, 2019). Depending on the soot formation process, individual spherules may be crystalline, amorphous, or partially crystalline (Baldelli & Rogak, 2019; Sadezky et al., 2005; Vander Wal et al., 2010).…”