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

Shijie Xu, Shenghui Zhong, Ahmad Hadadpour, Yan Zhang, Kar Mun Pang, Mehdi Jangi, Hesameddin Fatehi, Xue Song Bai

Research output: Contribution to journalArticlepeer-review

Abstract

Large-eddy simulations (LES) coupled with a partially-stirred reactor model and a finiterate chemistry are carried out to investigate the effects of n-heptane injection timing on the methanol fueled dual-fuel (DF) combustion. Methanol is premixed with air in a constant volume chamber (T=1000 K, ρ =14.8 kg/m3 ) to form a homogeneous mixture (equivalence ratio Φm of 0.3). Liquid fuel n-heptane is provided from a high pressure injector to mimic the pilot fuel injection in DF engines. First, mesh sensitivity analysis and LES model validation are conducted. The experimental data of Spray-H (n-heptane fueled) from the Engine Combustion Network is used for model validation. It is shown that the present mesh and LES model are capable of replicating the liquid and vapor penetration length, mixture fraction, temperature distribution, pressure rise profile and ignition delay time (IDT). Second, the effects of n-heptane injection timing are investigated, by varying the start of injection (SOI) time. The LES results reveal that there are three stage heat releases in the DF combustion. With the delay of SOI, the mass fraction of hydrogen peroxide in the ambient mixture increases, leading to an early formation of hydroxyl. Therefore, the two-stage IDTs of n-heptane decrease, while the ambient methanol IDT increases. Results also show the cool flame and hightemperature flame evolution after methanol auto-ignition. The cool flame disappears while the high-temperature flame is found near the injector nozzle, which leads to a relatively high heat release rate.
Original languageEnglish
Article number122445
JournalFuel
VolumeVolume 310, Part C
Early online date18 Nov 2021
DOIs
Publication statusE-pub ahead of print - 18 Nov 2021

Keywords

  • Dual-fuel combustion
  • Engine Combustion Network
  • Ignition
  • Injection timing
  • Large eddy simulation

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Organic Chemistry

Fingerprint

Dive into the research topics of 'Large-eddy simulation of the injection timing effects on the dual-fuel spray flame'. Together they form a unique fingerprint.

Cite this