Turbulent-flame speeds in methane–air mixtures were measured in a Taylor–Couette apparatus with counter-rotating cylinders, used to generate turbulence that is nearly homogeneous and isotropic over many integral length and time scales. While laminar-flame propagation is found to be influenced by the Darrieus– Landau instability and heat loss to the walls of the apparatus, turbulent-flame propag...

Dynamics of outwardly-propagating reaction fronts inspires both fundamental and practical interests. While for the former we can mention in pass supernovae explosions and measurements of laminar flame speeds of reactive mixtures, the latter is relevant to the operation of engines and prevention of spark-initiated hazards such as accidental or intentional explosions. While a pointy-ignited, expa...

In an opposed-jet diffusion flame experiment, under certain conditions, after the extinction of the diffusion flame, an edge flame can be obtained. This ring-shaped edge flame was first reported in 1959 by Potter and Butler but received little attention. It was reported again recently in a numerical and an experimental work and is responsible for an interesting transition between two distinct b...

This paper compares numerical simulations with experiments to study the deformation of lean premixed spherically expanding flames under a negative direct current (DC) electric field. The experiments, including the flame deformation and the ionic distribution on the flame surface were investigated in a mesh to mesh electric field. Besides, a numerical model of adding an electric body force to th...

Reduction of nitric oxides (NOx) in aircraft engines and in gas turbines by lean combustion is of great interest in the design of novel combustion systems. However, the stabilization of the flame under lean conditions is a main issue. In this context, the present work investigates the effects of sinusoidal dielectric barrier discharge (DBD) on a lean inverse diffusive methane/air flame in a Bun...

Various flame tracking techniques are often used in hydrodynamic simulations. Their use is indispensable when resolving actual scale of the flame is impossible. We show that parameters defining “artificial flame” propagation found from model systems may yield flame velocities several times distinct from the required ones, due to matter expansion being ignored in the models. Integral effect of m...

To understand the propagation characteristics of methane-air deflagration flames and in an obstacle-filled tube, a high-speed color video camera, photoelectric sensors, and pressure transducers were used to test the deflagration flame propagating parameters. The tests were run in a 1500 mm long plexiglass tube with a 100 × 100 mm square cross-section. The obstacles included four types of repeat...

BACKGROUND Temporomandibular dysfunction is one of the most complex disorders of the body, capable of unchaining alterations in the mandibular movements which in turn can cause damage not only to speech articulation but also to the quality of voice. In the literature, the relationship between the symptomatology severity levels of this dysfunction and their influence on vocal production has been...

A new modeling strategy is developed to introduce tabulated chemistry methods in LES of turbulent premixed combustion. The objective is to recover the correct laminar flame propagation speed of the filtered flame front when subgrid scale turbulence vanishes. The filtered flame structure is mapped by 1-D filtered laminar premixed flames. Closure of the filtered progress variable and the energy b...

The aim of this paper is to present some improvements in the metrology of forest fire flames by coupling image processing and radiative heat flux measurement. A new metrological tool using a visual video camera and a specific multiple thermal sensor is proposed. By means of an appropriate segmentation algorithm and the Direct Linear Transformation, the image processing methodology gives the for...