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...

Multidimensional unsteady numerical simulations were carried out to explore the influence of thermal radiation on propagation and structure layered coal dust explosions. The simulation solved reactive compressible Navier-Stokes equations coupled an Eulerian kinetic-theory-based granular multiphase model. heat transfer is modeled by solving equation using third-order filtered spherical harmonics...

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...

Motivated by potential applications in architecture, we study Darboux cyclides. These algebraic surfaces of order ≤ 4 are a superset of Dupin cyclides and quadrics, and they carry up to six real families of circles. Revisiting the classical approach to these surfaces based on the spherical model of 3D Möbius geometry, we provide computational tools for the identificiation of circle families on ...

The importance of nanosized material in many contemporary applications is already known. However special properties such as superparamagnetism, semi-conducting and photocatalysis are unique to single metallic oxide. Recent advances in information technology, catalysis, and medicine often require materials that posses a combination of two or more of these properties. Nanocomposite materials pres...

The excess enthalpy flames and their dynamics below the flammability limit are studied by considering two flames that propagate in opposite directions in parallel channels. The model enables the coupling between the external heat loss, convection preheating, diffusion transport and finite rate chemistry. Analytical expressions for the flame temperature, separation distance, and extinction limit...

In this study, the effect of flame intrinsic instability on the flame structural characteristics of hydrogen/air mixtures premixed at various equivalence ratios were experimentally investigated from the macroscopic and microscopic perspectives, respectively. The correlation degree and the relative deformation degree were defined to quantitatively study the global flame structural characteristic...