Advanced

Study of the Early Flame Development in a Spark-Ignited Lean Burn Four-Stroke Large Bore Gas Engine by Fuel Tracer PLIF

Wellander, Rikard LU ; Rosell, Joakim LU ; Richter, Mattias LU ; Aldén, Marcus LU ; Andersson, Öivind LU ; Johansson, Bengt LU ; Duong, Jeudi LU and Hyvönen, Jari LU (2014) In SAE International Journal of Engines 7(2). p.928-936
Abstract
In this work the pre- to main chamber ignition process is studied in a Wärtsilä 34SG spark-ignited lean burn four-stroke large bore optical engine (bore 340 mm) operating on natural gas. Unburnt and burnt gas regions in planar cross-sections of the combustion chamber are identified by means of planar laser induced fluorescence (PLIF) from acetone seeded to the fuel. The emerging jets from the pre-chamber, the ignition process and early flame propagation are studied. Measurements reveal the presence of a significant temporal delay between the occurrence of a pressure difference across the pre-chamber holes and the appearance of hot burnt/burning gases at the nozzle exit. Variations in the delay affect the combustion timing and duration. The... (More)
In this work the pre- to main chamber ignition process is studied in a Wärtsilä 34SG spark-ignited lean burn four-stroke large bore optical engine (bore 340 mm) operating on natural gas. Unburnt and burnt gas regions in planar cross-sections of the combustion chamber are identified by means of planar laser induced fluorescence (PLIF) from acetone seeded to the fuel. The emerging jets from the pre-chamber, the ignition process and early flame propagation are studied. Measurements reveal the presence of a significant temporal delay between the occurrence of a pressure difference across the pre-chamber holes and the appearance of hot burnt/burning gases at the nozzle exit. Variations in the delay affect the combustion timing and duration. The combustion rate in the pre-chamber does not influence the jet propagation speed, although it still has an effect on the overall combustion duration. PLIF images also show that there is mainly lean unburnt gas, originating from the main-chamber, that exit the pre-chamber in the initial phase of ignition, indicating incomplete mixing of the gases in the pre-chamber prior ignition. These findings are also supported by CFD modeling performed on the Wärtsilä 34SG combustion system. Similar to the air entrainment in a diesel spray, the jets exiting the pre-chamber causes pronounced entrainment of compressed fresh charges into the burning jets, thus promoting heat transfer and subsequent ignition. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
SAE International Journal of Engines
volume
7
issue
2
pages
928 - 936
publisher
SAE
external identifiers
  • scopus:84903385227
ISSN
1946-3944
DOI
10.4271/2014-01-1330
language
English
LU publication?
yes
id
98443a00-a07b-4fb5-88b0-20366bcd71c8 (old id 4858040)
alternative location
http://papers.sae.org/2014-01-1330/
date added to LUP
2014-12-10 17:05:46
date last changed
2017-08-27 03:11:22
@article{98443a00-a07b-4fb5-88b0-20366bcd71c8,
  abstract     = {In this work the pre- to main chamber ignition process is studied in a Wärtsilä 34SG spark-ignited lean burn four-stroke large bore optical engine (bore 340 mm) operating on natural gas. Unburnt and burnt gas regions in planar cross-sections of the combustion chamber are identified by means of planar laser induced fluorescence (PLIF) from acetone seeded to the fuel. The emerging jets from the pre-chamber, the ignition process and early flame propagation are studied. Measurements reveal the presence of a significant temporal delay between the occurrence of a pressure difference across the pre-chamber holes and the appearance of hot burnt/burning gases at the nozzle exit. Variations in the delay affect the combustion timing and duration. The combustion rate in the pre-chamber does not influence the jet propagation speed, although it still has an effect on the overall combustion duration. PLIF images also show that there is mainly lean unburnt gas, originating from the main-chamber, that exit the pre-chamber in the initial phase of ignition, indicating incomplete mixing of the gases in the pre-chamber prior ignition. These findings are also supported by CFD modeling performed on the Wärtsilä 34SG combustion system. Similar to the air entrainment in a diesel spray, the jets exiting the pre-chamber causes pronounced entrainment of compressed fresh charges into the burning jets, thus promoting heat transfer and subsequent ignition.},
  author       = {Wellander, Rikard and Rosell, Joakim and Richter, Mattias and Aldén, Marcus and Andersson, Öivind and Johansson, Bengt and Duong, Jeudi and Hyvönen, Jari},
  issn         = {1946-3944},
  language     = {eng},
  number       = {2},
  pages        = {928--936},
  publisher    = {SAE},
  series       = {SAE International Journal of Engines},
  title        = {Study of the Early Flame Development in a Spark-Ignited Lean Burn Four-Stroke Large Bore Gas Engine by Fuel Tracer PLIF},
  url          = {http://dx.doi.org/10.4271/2014-01-1330},
  volume       = {7},
  year         = {2014},
}