This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Fractal Dimension Growth in Flame Front Wrinkles during the Early Phase of Flame Propagation in an SI Engine
Technical Paper
2003-01-1840
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Turbulent premixed flame fronts during the early phase of flame propagation were visualized by a laser-light sheet technique in an optically accessible spark ignition engine. Time-resolved continuous images of wrinkling flame fronts were captured by a high-speed video camera until roughly 20% of total fuel was consumed. The image data were processed to measure the fractal dimension D2 in a time series for each cycle. The results show that the fractal dimension D2 is close to unity just after the spark ignition and then increases with time as the flame propagates. It is also shown that the fractal dimension increases more quickly as engine speed increases. The temporal rate of increase in the fractal dimension, ΔD2/Δt, was obtained from the D2 data and the relationship between ΔD2/Δt and D2 was examined. The result reveals that the higher D2 is, the lower ΔD2/Δt becomes from a positive value to a minus value, crossing zero when D2 reaches a critical value D2C. The following empirical equation was derived from the average of the relationships over many cycles: dD2/dt = -{D2 - D2C}/τ (τ : time constant). The critical fractal dimension D2C and the time constant τ were correlated with unburned mixture turbulence intensities, which were measured by a cross-correlation PIV technique. Compared with other combustion models, the present model produced a reasonable result.
Citation
Suzuki, K. and Nishiwaki, K., "Fractal Dimension Growth in Flame Front Wrinkles during the Early Phase of Flame Propagation in an SI Engine," SAE Technical Paper 2003-01-1840, 2003, https://doi.org/10.4271/2003-01-1840.Also In
References
- Zhao, X. Matthews, R. D. Ellzey, J. L. “Numerical Simulations of Combustion in SI Engines: Comparison of the Fractal Flame Model to the Coherent Flame Model,” Proc. COMODIA94 157 162 1994
- Herweg, R. Maly, R. R. “A Fundamental Model for Flame Kernel Formation in S. I. Engines,” SAE Paper 922243 1992
- Heel, B. Maly, R. Weller, H. G. Gosman, A. D. “Validation of Combustion Model over Range of Speed, Load, Equivalence Ratio and Spark Timing,” Proc. COMODIA98 255 260 1998
- Zhu, T. T. O'Rourke, P. J. Matthews, R. D. “A Multi Dimensional Numerical Model for Turbulent Premixed Flames with Fractal Geometries,“ SAE Paper 952386 1995
- Matthews, R. D. Hall, M. J. Dai, W. Davis, G. C. “Combustion Modeling in SI Engines with a Peninsula-Fractal Combustion Model,” SAE Paper 960072 1996
- Santavicca, D. A. Liou, D. North, G. L. “A Fractal Model of Turbulent Flame Kernel Growth,” SAE Paper 900024 1990
- Gouldin, F. C. “An Application of Fractals to Modeling Premixed Turbulent Flames,” Combustion and Flame 68 249 266 1987
- Hall, M. J. Dai, W. Matthews, R. D. “Fractal Analysis of Turbulent Premixed Flame Images from SI Engines,” SAE Paper 922242 1992
- zur Loye, A. O. Bracco, F. V. “Two-Dimensional Visualization of Premixed-Charge Flame Structure in an IC Engine,” SAE Paper 870454 1987
- Ikegami, M. Shioji, M. Nishimoto, K. “Turbulence intensity and Spatial Integral Scale during Compression and Expansion Strokes in a Four-Cycle Reciprocating Engine,” SAE Paper 870372 1987
- Hamamoto, Y. Tomita, E. “Turbulent Characteristics of Swirl in an I. C. Engine Cylinder,” JSAE Review 9 4 4 9 1988
- Kobayashi, H. Nakashima, T. Tamura, T. Maruta, K. Niioka, T. “Turbulent Measurements and Observations of Turbulent Premixed Flames at Elevated Pressures up to 3.0 MPa,” Combustion and Flame 108 104 117 1997
- Yoshiyama, S. Hamamoto, Y. Tomita, E. Zhong, Z. “Fractal Characteristics of Turbulent Premixed Flame in a Closed Vessel and a Spark-Ignition Engine,” Proc. COMODIA98 209 214 1998
- Hill, P. G. Hung, J. “Laminar Burning Velocities of Stoichiometric Mixtures of Methane with Propane and Ethane Additives,” Combust. Sci. and Tech. 60 7 30 1988
- Gülder, Ö. L. Smallwood, G. J. Wong, R. Snelling, D. R. Smith, R. “Flame Front Surface Characteristics in Turbulent Premixed Propane/Air Combustion,” Combustion and Flame 120 407 416 2000