In this study, a three-dimensional Direct Numerical Simulation of an open turbulent jet spray flame has been used to investigate the statistical behaviour displacement speed Sd and its components provide physical explanations for observed behaviours at different axial locations downstream exit. The exhibits fuel-lean conditions close exit but fuel-rich have further due evaporation fuel droplets...

A theoretical–numerical analysis based on the second law of thermodynamics is used to examine the propagation of laminar H2-enriched CH4–air flames. The analysis is based on computing the various entropy generation terms in a transient reacting flow field. A comprehensive, time-dependent computational model, which employs a detailed description of chemistry and transport, is used to simulate th...

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We develop a one-dimensional theoretical model for thermals burning in Type Ia supernovae based on the entrainment assumption of Morton, Taylor and Turner. Extensions of the standard model are required to account for the burning and for the expansion of the thermal due to changes in the background stratification found in the full star. The model is compared with high-resolution three-dimensiona...

A correct prediction of the ignition process represents a fundamental pre-requisite for a successful CFD simulation of combustion SI engines. Ignition involves many scales, physical and chemical phenomena that need to be described in detail. Within this context, the authors developed a Lagrangian model that can be used to predict the first stages of the combustion process in SI engines, when th...

Lean fueling of spark ignited (SI) engines is a valid method for increasing efficiency and reducing nitric oxide (NOx) emissions. Gasoline direct injection (GDI) allows better fuel economy with respect to the port-fuel injection configuration, through greater flexibility to load changes, reduced tendency to abnormal combustion, and reduction of pumping and heat losses. During homogenous charge ...

We study the large time asymptotic speeds (turbulent flame speeds sT ) of the simplified Hamilton-Jacobi (HJ) models arising in turbulent combustion. One HJ model is G-equation describing the front motion law in the form of local normal velocity equal to a constant (laminar speed) plus the normal projection of fluid velocity. In level set formulation, G-equations are HJ equations with convex (L...