Large-eddy simulation of the injection timing effects on the dual-fuel spray flame

Large-eddy simulations (LES) coupled with a partially-stirred reactor model and finite-rate chemistry are carried out to investigate the effects of n-heptane injection timing on methanol fueled dual-fuel (DF) combustion. Methanol is premixed air in constant volume chamber (T=1000 K, ρ=14.8 kg/m3) form homogeneous mixture (equivalence ratio ϕm 0.3). Liquid fuel provided from high pressure injector mimic pilot DF engines. First, mesh sensitivity analysis LES validation conducted. The experimental data Spray-H (n-heptane fueled) Engine Combustion Network used for validation. It shown that present capable replicating liquid vapor penetration length, fraction, temperature distribution, rise profile ignition delay time (IDT). Second, investigated, by varying start (SOI) time. results reveal there three stage heat releases With SOI, mass fraction hydrogen peroxide ambient increases, leading an early formation hydroxyl. Therefore, two-stage IDTs decrease, while IDT increases. Results also show cool flame high-temperature evolution after auto-ignition. disappears found near nozzle, which leads relatively release rate.