Zero-Dimensional Spark Ignition Combustion Modeling - A Comparison of Different Approaches 2013-24-0022
Internal combustion engines development with increased complexity due to CO2 reduction and emissions regulation, while reducing costs and duration of development projects, makes numerical simulation essential. 1D engine simulation software response for the gas exchange process is sufficiently accurate and quick. However, combustion simulation by Wiebe function is poorly predictive.
The objective of this paper is to compare different approaches for 0D Spark Ignition (SI) modeling. Versions of Eddy Burn Up, Fractal and Flame Surface Density (FSD) models have been coded into GT-POWER platform, which connects thermodynamics, gas exchange and combustion sub-models. An initial flame kernel is imposed and then, the flame front propagates spherically in the combustion chamber. Flame surface is tabulated as a function of piston position and flame radius. The modeling of key features of SI combustion such as laminar flame speed and thickness and turbulence was common. This comparison focuses on the impact of turbulence on the flame front and shows the predictive capabilities of each approach.
Those three approaches have been evaluated against experimental data for several steady state operating points of a single-cylinder engine. Cylinder pressure is predicted satisfactorily. Burn rates are well predicted for the period of a freely propagating flame front, that is before flame-wall interaction occurs. The FSD model physically considers the impact of turbulence on the flame for various turbulence scales, unlike the other two models which demand more calibration parameters. It is shown that additional modeling must be incorporated so that the flame-wall interaction is taken into account.