Large eddy simulation of n-Dodecane spray combustion in a high pressure combustion vessel
Författare
Summary, in English
Autoignition and stabilization of n-Dodecane spray combustion under diesel engine like conditions are investigated using large eddy simulation and detailed chemical kinetics. The Spray A cases of Engine Combustion Network (ECN) with ambient temperatures of 900 K and 1000 K are considered. Two-stage ignition behavior is predicted in the studied conditions. It is found that the first-stage ignition occurs on the fuel-lean mixture, whereas the second-stage ignition starts on the fuel-rich mixture. The first stage ignition in the fuel-lean mixture promotes the first and the second stage ignition in the fuel-rich mixture owing to rapid turbulent mixing. Two mechanisms, autoignition and flame propagation coupling with the low temperature ignition, are used to explain the lift-off position and stabilization of the combustion process. They compete with each other, and their relative importance depends on the ambient temperature. The ambient temperature is shown to affect the soot emission in the flame through its influences on the lift-off length and the reaction zone structure. Higher ambient temperature results in a shorter lift-off length, which gives rise to higher soot emission due to the lower air entrainment to the fuel-rich zone in front of the flame. In the lower temperature case, the flame is stabilized by an autoignition induced flame front where a considerable amount of fuel is oxidized to CO at the leading front of the flame. Consequently, it reduces the soot formation in the flame. (C) 2014 Elsevier Ltd. All rights reserved.
Publiceringsår
2014
Språk
Engelska
Sidor
373-381
Publikation/Tidskrift/Serie
Applied Energy
Volym
136
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Fluid Mechanics and Acoustics
Nyckelord
- Diesel combustion
- Autoignition
- Flame stabilization
- Large eddy
- simulation
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1872-9118