The response of lean (φ 0.4) premixed hydrogen flames to maintained homogeneous isotropic turbulence is investigated using detailed numerical simulation in an idealised three-dimensional configuration over a range of Karlovitz numbers from 10 to 1562. In particular, a focus is placed on turbulence sufficiently intense that the flames can no longer be considered to be in the thin reaction burnin...

1. Introduction Premixed turbulent flames are of increasing practical importance and remain a significant research challenge in the combustion community. These flames have the potential to operate cleanly and efficiently over a broad range of fuels, and therefore to represent a key element in the implementation of low-emissions burners for a variety of industrial applications. However, it is di...

Direct numerical simulation (DNS) is used to study auto–ignition of turbulent diffusion flames. A novel, all–Mach number algorithm developed by Doom et al is used. The chemical mechanism is a nine species, nineteen reaction mechanism for H2 and Air from Mueller at el. 2 Simulations of three dimensional turbulent diffusion flames are performed. Isotropic turbulence is superimposed on an unstrain...

Fully developed stationary premixed flames are obtained by DNS in an incoming homogeneous isotropic turbulent flow. Analysis based on the Favre-averaged transport equation of turbulent kinetic energy shows that pressure gradient term and pressure work term increase turbulent kinetic energy in the flame region, and these terms produce anisotropic turbulence. The counter-gradient diffusion domina...

This paper describes an analysis of acoustic wave scattering by turbulent premixed flames with moving, convoluted fronts that have random and possibly fractal characteristics. Such interactions play a role in the characteristic unsteadiness observed in turbulent combustion processes. The problem is posed with an integral formulation of the wave equation and assumes that the smallest scales of f...

Studies of radiation emissions from turbulent buoyant diffusion flames impinging on structural elements have applications to the development of fire models and estimation of structural integrity under large heat loads. An experimental and numerical study of radiation emissions from turbulent buoyant diffusion flames with and without impingement on a flat plate is reported. The steel plate was s...

Even if the goal of reducing NOx emissions pushes towards the use of premixed combustion, moderately swirling turbulent non-premixed flames are still widely employed in both industrial furnaces and gas turbines, because of their stable and safe behaviour in a wide range of fuels and operating conditions. Computational Fluid Dynamics (CFD) has become in recent years a key tool for the design of ...

In recent years attention of researchers has been focused on the combustion generated particles in order to have a deeper knowledge on their formation and develop combustion systems with higher efficiency and lower environmental impact [1,2]. Opposed-flow configuration allows to study behavior and sooting tendency of fuels, avoiding fluidodynamic problems fundable in diffusion flames laminar or...

This paper is directed towards understanding how composition of the coal transport medium (primary CO2 and O2) affects the observed ignition stand-off distance in 40 kW co-axial turbulent diffusion, oxy-coal flames, supported in a specially designed combustion test rig, rated at 100 kW. First, a methodology to define and quantify the observed ignition stand-off distance in laboratory combustor ...

Abstract A flamelet-based approach that accounts for turbulence-chemistry interaction has been formulated to simulate NOx formation in turbulent lean premixed combustion. In the simulations, the species NO is transported and solved with the chemical source term being modelled through its formation in flame fronts and its formation rate in post-flame regions. The flame-front NO and post-flame NO...