The Effect of Chamber Geometry on Spark-Ignition Engine Combustion

Comparação Entre Os Modelos De Combustão Wiebe E Fractal Para Simulação Computacional De Um Motor Flex Operando Com Diferentes Misturas De Gasolina-Etanol

“…Para simular o modelo de combustão fractal, foi usado o modelo de turbulência de duas equações K-k, que é representado pelas seguintes equações [10]:…”

Numerical Simulation Techniques for the Prediction of Fluid-Dynamics, Combustion and Performance in IC Engines Fuelled by CNG

“…Although the magnitude of such a maximum depends, among other factors, on the configuration of the combustion chamber and, to a lesser extent, on the intake system, its presence is generally modelled by means of heuristic approaches that add turbulence during compression and combustion. As an example, it can be seen that, in (Baratta et al, 2006(Baratta et al, , 2008Poulos & Heywood, 1983), as soon as the combustion starts, Eq. (17) is no longer integrated, and the evolution of the turbulence intensity and of the spatial macro scale is calculated by assuming conservation of angular momentum for large scale eddies, which gives rise to an increase in the unburned-gas turbulence.…”

“…It is worth pointing out that the accuracy of a turbulent burning-speed model depends to a great extent on the unburned-gas turbulence evolution during combustion, which is normally thought to present a maximum near firing TDC (Baratta et al, 2008, Bozza et al, 2005, Heywood, 1988Poulos & Heywood, 1983;Yoshiyama et al, 2001). Although the magnitude of such a maximum depends, among other factors, on the configuration of the combustion chamber and, to a lesser extent, on the intake system, its presence is generally modelled by means of heuristic approaches that add turbulence during compression and combustion.…”

“…The turbulence model results can also be www.intechopen.com used by the in-cylinder heat-transfer sub-model, in order to derive a value for the convective heat-transfer coefficient. A rather simple, but quite widely applied model is the K-k one (Poulos & Heywood, 1983), which is based on a zero-dimensional energy cascade from the mean flow to the viscous eddy dissipation. According to such a model, the rates of change in the mean flow kinetic energy ( …”

“…x e being the entrained mass fraction (Brown et al, 1996;Grill et al, 2006;Hattrel et al, 2006;Poulos & Heywood, 1983;Wahiduzzaman et al, 1993). The rate of laminar burnout in eq.…”