The wavefronts associated with a one-dimensional combustion model with Arrhenius kinetics and no heat loss are analyzed within the high Lewis number perturbative limit. This situation, in which fuel diffusivity is small in comparison to that of heat, is appropriate for highly dense fluids. A formula for the wavespeed is established by a non-standard application of Melnikov’s method and slow man...

A phase-field model of non-isothermal solidification in dilute binary alloys is used to study the variation of growth velocity, dendrite tip radius and radius selection parameter as a function of Lewis number at fixed undercooling. By the application of advanced numerical techniques we have been able, for the first time, to extend the analysis to Lewis numbers of order 10000, which are realisti...

We study a mathematical model for high Lewis number combustion processes with the reaction rate of the form of an Arrhenius aw with or without an ignition cut-off. An efficient method for the proof of the existence and uniqueness of combustion fronts is rovided by geometric singular perturbation theory. The fronts supported by the model with very large Lewis numbers are small erturbations of th...

A phase-field model of nonisothermal solidification in dilute binary alloys is used to study the variation of growth velocity, dendrite tip radius, and radius selection parameter as a function of Lewis number at fixed undercooling. By the application of advanced numerical techniques, we have been able to extend the analysis to Lewis numbers of order 10 000, which are realistic for metals. A lar...

Spherical diffusion flames supported on a porous sphere were studied numerically and experimentally. Experiments were performed in 2.2 s and 5.2 s microgravity facilities. Numerical results were obtained from a Chemkin-based program. The program simulates flow from a porous sphere into a quiescent environment, yields both steady-state and transient results, and accounts for optically thick gas-...

We establish existence of travelling fronts in thermo-diffusive systems of the KPP type in a shear flow with an arbitrary Lewis number and a positive heat-loss at the boundary. We then prove that the leftover concentration behind the front is positive, and that it is small when the heat-loss is small. On the other hand, when the heat-loss approaches a critical value, the temperature becomes uni...

In this work we present the effect of Reynolds and Lewis numbers on fuel droplet vaporization n-heptane. This study allows us to fully understand phenomenon fine droplets (spray) in energy systems order improve combustion efficiency, reduce formation pollutants unburnt materials such as carbon monoxide Nox. The is based an analytical solution governing equations process by calculating diameter ...

The role of Helicobacter pylori lipopolysaccharide (LPS) Lewis antigens in infection is still not well known. We investigated the influence of Lewis antigen expression by H. pylori on its internalization by AGS cells and the epithelium of human gastric xenografts in nude mice using isogenic mutants in LPS biosynthetic genes. In vivo, colonization rates were unaffected by the change in H. pylori...