The dynamics of the explosive burning process is highly sensitive to the flame speed model in numerical simulations of type Ia supernovae. Based upon the hypothesis that the effective flame speed is determined by the unresolved turbulent velocity fluctuations, we employ a new subgrid scale model which includes a localised treatment of the energy transfer through the turbulence cascade in combin...

New combustion systems based on ultra-lean premixed combustion have the potential for dramatically reducing pollutant emissions in transportation systems, heat, and stationary power generation. However, lean premixed flames are highly susceptible to fluiddynamical combustion instabilities, making robust and reliable systems difficult to design. Lowswirl burners are emerging as an important tech...

In order to respond the increased demand for clean energy without harming atmosphere through polluting emissions, production from hydrogen combustion become largely used. This work presents a numerical study of injection conditions effect on structure H2-air diffusion flame. The aim is reproduce practical case non-polluting and resulting in very high temperatures. configuration composed two axi...

One of the well-known properties of turbulent, premixed flames is that their speed of propagtion is correlated to the intensity of the turbulence they encounter. A simple consequence is that these types of flames are inherently unstable. Given a source of turbulence, if the flame is propagating faster than the mean flow, it will drift upstream and encounter increased turbulent intensities that ...

At a density near a few ×10 g cm, the subsonic burning in a Type Ia supernova enters the distributed regime (high Karlovitz number). In this regime, turbulence disrupts the internal structure of the flame, and so the idea of laminar burning propagated by conduction is no longer valid. The nature of the burning in this distributed regime depends on the turbulent Damköhler number (DaT ), which st...

In order to respond the increased demand for clean energy without harming atmosphere through polluting emissions, Energy production from hydrogen combustion become largely used. This work presents a numerical study of injection conditions effect on structure H2-Air diffusion flame. The aim is reproduce practical case non-polluting and resulting in very high temperatures. configuration composed ...

A comprehensive numerical analysis has been conducted to study the combustion of a double-base homogeneous propellant in a rocket motor. Emphasis was placed on the motor internal flow development and its influence on propellant combustion. The formulation is based on the Favre-averaged, filtered equations for the conservation laws and takes into account finite-rate chemical kinetics and variabl...

The purpose of this study is to investigate the effect of radiation heat transfer on temperature distribution and heat flux to the walls of a diesel engine. A diffusion flame is modeled in a simple cylindrical geometry and boundary conditions are defined. A specific solver which can model the turbulent diffusion flame by considering radiation in participating media is used to solve the problem....

In modeling turbulent reactive flows based on the transport equation for the joint probability density function (jpdf) of velocity and composition, the change in fluid composition due to convection and reaction is treated exactly, while molecular mixing has to be modeled. A new mixing model is proposed, which is local in composition space and which seeks to address problems encountered in flows...

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...