Combustion characteristics of n-heptane spray combustion in a low temperature reform gas/air environment

Research output: Contribution to journalArticlepeer-review

Authors

  • Shenghui Zhong
  • Shijie Xu
  • Xue-Song Bai
  • Ahmad Hadadpour
  • Fan Zhang
  • Qing Du
  • Zhijun Peng

Colleges, School and Institutes

Abstract

This paper presents a large eddy simulation study of n-heptane spray combustion in an n-heptane low temperature reform (LTR) gas environment in a constant volume combustion chamber, under conditions relevant to single-fuel reactivity controlled compression ignition (RCCI) combustion engines. The LTR gas is made up of partially oxidized intermediate species from rich n-heptane/air mixture in an external constant temperature reformer. It is found that a higher reform temperature results in a longer ignition delay time of the n-heptane spray and a higher liftoff length, due to the chemical effect of the LTR gas and the difference in the reaction zone structures. A significantly different spray flame structure is identified in the RCCI case from that of single-fuel spray combustion. After the onset of high temperature ignition, a double-layer flame structure is established in the RCCI case, with a diffusion flame layer and a lean premixed flame layer. The lean premixed flame affects the flow field, which significantly suppresses the mixing around the spray tip. As a result, the RCCI case exhibits a lower NOx formation but a higher soot formation than the single-fuel case.

Details

Original languageEnglish
Article number120377
JournalFuel
Volume293
Early online date26 Feb 2021
Publication statusE-pub ahead of print - 26 Feb 2021