Numerical study of combustion of the diesel fuel sprayed with a steam jet in a prospective burner device

Abstract

A prospective laboratory-scale burner device that employs a concept of liquid fuel spraying in the high-speed superheated steam jet is considered. The presented work is devoted to numerical study of aerothermochemical processes occurring in this novel-design burner during the combustion of diesel fuel sprayed with axial jet of water steam. The mathematical model is based on Euler-Lagrange approach for two-phase turbulent reacting flow description applied in 2D axisymmetric steady-state formulation. The vaporized diesel fuel combustion is described via EDC model with chemical kinetics mechanism for n-heptane (30 species, 66 reactions). The two-step soot model is also used, as well as NOx prediction at post-processing stage. The fields of velocity, temperature, heat fluxes, gas species and disperse phase concentrations, including soot and NOx, have been obtained from numerical simulation for a typical operational mode with diesel supply rate of 1.2 kg/hour and water steam flowrate of 0.8 kg/hour. Analysis of these flowfield data has allowed to reveal the two-layer coaxial structure of reacting flow (consisting of relatively cold near-axis jet layer and the coaxial layer formed by the hot recirculation zone) inside the burner.