Effects of Injection Timing on Fluid Flow Characteristics of Partially Premixed Combustion Based on High-Speed Particle Image Velocimetry

Research output: Contribution to journalArticle

Abstract

Partially Premixed Combustion (PPC) is a promising combustion concept ,based on judicious tuning of the charge stratification, to meet the increasing demands of emission legislation and to improve fuel efficiency. Longer ignition delays of PPC in comparison with conventional diesel combustion provide better fuel/air mixture which decreases soot and NOx emissions. Moreover, a proper injection timing and strategy for PPC can improve the combustion stability as a result of a higher level of fuel stratification in comparison with the Homogeneous Charge Compression Ignition (HCCI) concept. Injection timing is the major parameter with which to affect the level of fuel and combustion stratification and to control the combustion phasing and the heat release behavior. The scope of the present study is to investigate the fluid flow characteristics of PPC at different injection timings. To this end, high-speed Particle Image Velocimetry (PIV) is implemented in a light-duty optical engine to measure fluid flow characteristics, including the flow fields, mean velocity and cycle-resolved turbulence, inside the piston bowl as well as the squish region with a temporal resolution of 1 crank angle degree at 800 rpm. Two injectors, having 5 and 7 holes, were compared to see their effects on fluid flow and heat release behavior for different injection timings. Reactive and non-reactive measurements were performed to distinguish injection-driven and combustion-driven turbulence. Formation of vortices and higher turbulence levels enhance the air/fuel interaction, changing the level of fuel stratification and combustion duration. Results demonstrate clearly how turbulence level correlates with heat release behavior, and provide a quantitative dataset for validation of numerical simulations.

Details

Authors
  • Mohammad Izadi Najafabadi
  • Slavey Tanov
  • Lu Hua Wang
  • Bart Somers
  • Bengt Johansson
  • Nico Dam
Organisations
External organisations
  • Eindhoven University of Technology
  • King Abdullah University of Science and Technology
  • Dantec Dynamics A/S
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Energy Engineering
Original languageEnglish
JournalSAE International Journal of Engines
Volume10
Issue number4
Publication statusPublished - 2017 Mar 28
Publication categoryResearch
Peer-reviewedYes