Multiple flame regimes are encountered in industrial combustion chambers, where premixed, stratified and non-premixed regions may coexist. To obtain a predictive tool for pollutant formation predictions, chemical modeling must take into account the influence of such complex structure. The objective this article is to apply compare two reduced chemistry models on both laminar turbulent multi-reg...

We study the bifurcations of a ducted two-dimensional premixed flame using numerical simulations of the coupled dynamical system. When the flame position in the duct is changed the system undergoes transition to period-1, quasi-periodic, period-2, frequencylocked and chaotic oscillations via different bifurcations. For certain parameter ranges multiple stable solutions exist and the ultimate st...

The paper describes CFD modelling of lean hydrogen mixture deflagrations. Large eddy simulation (LES) premixed combustion model developed at the University of Ulster to account phenomena related to large-scale deflagrations was adjusted specifically for lean hydrogen-air flames. Experiments by Kumar (2006) on lean hydrogen-air mixture deflagrations in a 120 m vessel at initially quiescent condi...

We document and explain the existence of two distinct scaling regimes for the burning speed enhancement of an idealized premixed flame as a result of its distortion by an unsteady periodic shear. The simplified model used in the present study allows for a rigorous, quantitative explanation of the bending in the scaling exponent, either linear or sublinear in the shear intensity, in terms of a n...

In a recent numerical paper (Nicoli et al. Combust. Sci. Technol. vol. 186, pp. 103-119; 2014) [1], a model of isobaric flame propagation in lean sprays has been proposed. The initial state of the monodisperse mists was schematized by a system of individual alkane droplets initially located at the nodes of a facecentered 2D-lattice, surrounded by a saturated mixture of alkane and air. In the pr...

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...

A model for heat-recirculating micro combustor is developed. It investigates the structure of laminar, one-dimensional and steady state flame propagation in uniformly premixed wood particles with considering the effects of heat recirculation caused by configuration of micro combustor. The flame structure is divided into three regions: a preheat-devolatilization zone where the rate of the gas-ph...

Turbulent lean premixed dodecane/air flames are simulated in a doubly-periodic domain using detailed kinetics and transport over a range of Karlovitz number. We observe extensive thickening of thermal profiles through the flames that increases with turbulent intensity. The high Lewis number of the flames acts to suppress wrinkling of the flame resulting in considerably lower turbulent flame spe...

An idealized geometry corresponding to a premixed flame in stagnation-point flow is used to investigate the effects of catalysis on extending the extinction limits of nonadiabatic stretched flames. Specifically, a surface catalytic reaction is assumed to occur on the stagnation plane, thereby augmenting combustion in the bulk gas with an exothermic surface reaction characterized by a reduced ac...

In this study a multi-objective genetic algorithm approach is developed for determining new reaction rate parameters for the combustion of kerosene/air mixtures. The multi-objective structure of the genetic algorithm employed allows for the incorporation of both perfectly stirred reactor and laminar premixed flame data into the inversion process, thus producing more efficient reaction mechanisms.