Our primary energy consumption is supported in 81% by the combustion of fossil energy commodities (IEA, 2010). The demand on energy will grow by about 60% in the near future (Shell, 2008). The efficiency of the combustion processes is crucial for the environment and for the use of the remaining resources. At the Karlsruhe Institute of Technology the longterm project Collaborative Research Centr...

A numerical investigation of the structure and extinction of n-heptane/air partially premixed  ames in a counter ow conŽ guration is reported. The  ame is computed using a detailed reaction mechanism consisting of 275 elementary reactions and 41 species. The mechanism is validated by comparing its predictions with measurements for both the premixed and nonpremixed  ames. The partially premi...

The interaction of a vortex pair with a premixed flame serves as an important prototype for premixed turbulent combustion. In this study, we investigate the interaction of a counter-rotating vortex pair with an initially flat premixed methane flame. We compare computational solutions obtained using a timedependent, two-dimensional adaptive low Mach number combustion algorithm that incorporates ...

The interaction of a vortex pair with a premixed flame serves as an important prototype for premixed turbulent combustion. In this study, we investigate the interaction of a counterrotating vortex pair with an initially flat premixed methane flame. We focus on characterizing the mechanical nature of the flame-vortex interaction and on the features of the interaction strongly affected by fuel eq...

Various engine and shock tube studies have observed increased NOx emissions from the combustion of biodiesels relative to regular diesel and linked them to the degree of unsaturation or the number of double bonds in the molecular structure of long-chain biodiesel fuels. We report herein a numerical investigation on the structure and emission characteristics of triple flames burning n-heptane an...

The dual-fuel diesel engine (D.F.D.E) is a conventional diesel engine in which much of the energy released, hence power, comes from the combustion of gaseous fuel such as natural gas. The exhaust emission characteristics of the D.F.D.E needs further refinements, particularly in terms of reduction of Unburnt Hydrocarbons (U7HC) and Carbon Monoxide (CO) emission, because the concentration of thes...

We investigate the propagation of a premixed flame subject to thermal expansion through a narrow channel against a Poiseuille flow of large amplitude. This is the first study to consider the effect of a large-amplitude flow, characterised by a Péclet number of order one, Pe= O(1), on a variable-density premixed flame in the asymptotic limit of a narrow channel. It is also the first study on Tay...

where DZ is the diffusion coefficient of the mixture fraction. The scalar dissipation rate appears in many models for turbulent non-premixed combustion as, for instance, the flamelet model (Peters (1984), Peters (1987)), the Conditional Moment Closure (CMC) model (Klimenko & Bilger (1999)), or the compositional pdf model (O’Brien (1980), Pope (1985)). In common technical applications, it has be...

During the last decade extensive research has been made at Lund University, Sweden, on a lean premix (prevaporize) combustion concept with burnt gas recirculation and a metallic flame holder. From this concept a new lean premixed natural gas combustion chamber with internal combustion gas recirculation (CGR) has been developed for the V160/SOLO 161 Stirling engines. This combustor has ultra-low...

Homogenous Charge Compression Ignition (HCCI) is a mode of combustion in IC engines in which premixed fuel and air are ignited spontaneously. There is a belief that HCCI engines have a great potential to improve fuel consumption and reduce NOx emissions. In this study, a single zone, zero dimensional, thermo-kinetic model has been developed and a computer program with MATLAB software is use...