Title: Quasi-dimensional modelling of turbulence-driven phenomena in SI engines

Authors: Adolf Nefischer; Jens Neumann; Andrei Stanciu; Andreas Wimmer

Addresses: BMW AG, 80788 Muenchen, Germany ' BMW AG, 80788 Muenchen, Germany ' BMW AG, 80788 Muenchen, Germany ' Institute for Internal Combustion Engines and Thermodynamics, Graz University of Technology, 8010 Graz, Inffeldgasse 21/A, Austria

Abstract: In the present work, various basic approaches regarding the quasi-dimensional description of the combustion and the resulting wall heat transfer within SI engines are reviewed and analysed to promote the understanding and to enable modelling improvements. Owing to the dominant role of turbulence, models for the description of the turbulent flow in the combustion chamber are first analysed. The importance of taking into account the influence of combustion when calculating the wall heat transfer of various fuels is shown based on model comparisons. A hypothesis regarding the interaction of turbulence and combustion is also presented. A general formulation of the turbulent flame speed is developed covering the premixed combustion of different fuels. Measurements of the wall heat flux, optical examinations of the flame propagation and thermodynamic measurements are used for validation. Furthermore, good correlations between corresponding measurements and simulations with the derived phenomenological approaches are demonstrated.

Keywords: simulation; SI engines; turbulence; combustion; wall heat transfer; modelling; spark ignition engines; turbulent flow; turbulent flame speed; premixed combustion; wall heat flux; flame propagation; thermodynamic measurements.

DOI: 10.1504/IJVD.2014.065718

International Journal of Vehicle Design, 2014 Vol.66 No.3, pp.297 - 316

Available online: 09 Nov 2014 *

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