High-fidelity multi-scale simulation tools are critically important for examining energy conversion processes in which the coupling of complex chemical kinetics, molecular transport, continuum mixing and acoustics play important roles. The objectives of this thesis are: (i) to develop a state-of-the-art numerical approach to capture the wide spectra of spatio-temporal scales associated with rea...

The speed of propagation of a premixed turbulent flame correlates with the intensity of the turbulence encountered by the flame. One consequence of this property is that premixed flames in both laboratory experiments and practical combustors require some type of stabilization mechanism to prevent blow-off and flashback. The stabilization devices often introduce a level of geometric complexity t...

Recent progress in simulation methodologies and new, high-performance parallel architectures have made it is possible to perform detailed simulations of time-dependent multidimensional combustion phenomena using comprehensive kinetics mechanisms. However, as simulation complexity increases, it becomes more difficult to extract meaningful quantitative information about the flame from the numeric...

1. Introduction Premixed turbulent flames are of increasing practical importance and remain a significant research challenge in the combustion community. These flames have the potential to operate cleanly and efficiently over a broad range of fuels, and therefore to represent a key element in the implementation of low-emissions burners for a variety of industrial applications. However, it is di...

In the field of fluid engineering, controlling turbulent flows remains a crucial problem. This paper presents a basis of numerical methods and turbulence models for the large Eddy simulation. Simulation results include the unsteady analyses of complex flows, such as the vortex dynamics of turbulent jets subject to inlet perturbations and the reacting flow with flame propagation in a gas–turbine...

An idealized model for turbulent premixed flames is introduced. It consists of a scalar advection-reaction-diffusion equation that describes the interaction of a thin flame with a turbulentlike flow field acting on two separate scales. Rigorous asymptotic results as well as affordable and reliable direct numerical simulations are available to predict the effective large scale behavior of the id...

porous media has interesting features in compared with free flame combustion due to the extended of the lean flammability limits and lower emissions. advanced new generation of internal combustion (ic) engines are expected to have far better emissions levels both gaseous and particulate matter, at the same time having far lower fuel consumption on a wide range of operating condition. these crit...

The effects of spectral radiation absorption on the flame speed at normal and elevated pressures were experimentally and numerically investigated using the CO2 diluted outwardly propagating CH4-O2-He flames. Experimentally, the laminar burning velocities of CH4-O2-HeCO2 mixtures at both normal and elevated pressures (up to 5 atm) were measured by using a pressure-release type spherical bomb. Th...

A time-resolved numerical analysis of combustion dynamics of double-base homogenous solid propellant in a rocket motor is performed by means of a Large-Eddy Simulation (LES) technique. The physiochemical processes occurring in the flame zone and their influence on the unsteady flow evolution in the chamber are investigated in depth. A five-step reduced reaction mechanism is used to obtain the t...