Fractal approach to the evaluation of burning rates in the vicinity of the piston in a spark-ignition engine

Journal Article · Tue Nov 01 04:00:00 EST 2005 · Combustion and Flame

DOI:https://doi.org/10.1016/j.combustflame.2005.06.007· OSTI ID:20677737

Foucher, F; Mounaim-Rousselle, C ^[1]

---

1. Laboratoire de Mecanique et d'Energetique, Polytech'Orleans, Universite d'Orleans, Site Leonard de Vinci, 45072 Orleans cedex 1 (France)

The burning rate in the vicinity of a piston is estimated from a fractal analysis. The fractal parameters are determined from laser sheet tomography flame images for methane-air mixtures with three equivalence ratios (1, 0.9, 0.8) in a transparent spark-ignition engine. Two imaging configurations were used: five horizontal planes placed at different distances from the piston (0, 1, 2, 3, and 5 mm) and a vertical one passed through the center of the combustion chamber. The methodology proposed by Foucher et al. [F. Foucher, S. Burnel, C. Mounaim-Rousselle, Proc. Combust. Inst. 29 (2002) 751-757] allows the effect of cyclic variations to be avoided. The fractal formulation is modified to take into account the flame-piston distance and flame quenching. Far from the piston, evolution of the fractal dimension versus q{sup '}/S{sub L}{sup 0} is found to be in good agreement with literature results. Near the piston, the fractal dimension evolves significantly when the distance is about twice the integral length scale and tends toward 2, the fractal dimension of a laminar flame front. The quenching ratio parameter Q{sub R} is introduced to consider the quenching of the flame by the piston. Finally, the burning rate is determined as a function of the distance between the wall and the mean flame contour and compared to a flame density approach, and similar results are found.

• OSTI ID: 20677737
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 3 Vol. 143; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
AIR
COMBUSTION KINETICS
DISTANCE
FRACTALS
METHANE
PISTONS
SPARK IGNITION ENGINES