Numerical and experimental investigation of single and multi-injection ignition of F-24/ATJ blends

Martin Rieth, Jeongwon Kim, Eric Mayhew, Jacob Temme, Chol Bum Kweon, Paxton Wiersema, Tonghun Lee, Jacqueline H. Chen

Research output: Contribution to journalArticlepeer-review

Abstract

Conventional jet fuels can be blended with other fuels, including sustainable aviation fuels (SAFs) to provide fuel flexibility and to reduce emissions. However, differences in fuel properties including the derived cetane number (measure of ignitability), together with low-temperature high-altitude flight conditions, pose significant challenges for reliable operation in aviation compression-ignition engines. Multi-injection strategies have been shown to enhance ignition reliability by providing a reactive mixture through an early pilot injection that boosts the ignition of the main injection. While the effectiveness of such strategies has been demonstrated experimentally and to some extent with simplified low-order simulations for conventional fuels, details of the ignition enhancement process are still not known. In the present study, we demonstrate the effectiveness of such strategies for a 40/60 ratio blend of F-24 and alcohol-to-jet (ATJ) fuel experimentally and numerically. Experiments are conducted in an optical chamber, using Schlieren, planar laser induced fluorescence and chemiluminescence imaging. Numerical data is provided by means of direct numerical simulation (DNS) of a simplified configuration resembling the experiments, incorporating a new reduced CN30 chemical mechanism (equivalent to the blend of F-24 and ATJ). The DNS are compared to the experiments in terms of the overall ignition process, and then analyzed with respect to the impact of the pilot injection on the ignition process, and the role of turbulent mixing in the ignition process. Clear differences between the ignition process with single injection versus a pilot-main strategy are shown.

Original languageEnglish (US)
Article number105341
JournalProceedings of the Combustion Institute
Volume40
Issue number1-4
DOIs
StatePublished - Jan 2024

Keywords

  • Alcohol-to-jet-fuel
  • Aviation compression ignition engine
  • Ignition
  • Multi-injection
  • Sustainable aviation fuel

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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