The ignition of spray flames is a process of stochastic nature, especially relevant to the highaltitude relight of aeroengines. The present work aims to quantify the role of spray inhomogeneities in a realistic droplet-laden ignition set-up through Direct Numerical Simulations (DNS). Computations of the ignition process of weakly turbulent ethanol ...
Previous work demonstrated Ca2Fe2O5 (C2F) can react in a blast furnace gas (BFG) with PCO/PCO2 ratio of ∼1, despite of its reduction to CaO + Fe requiring a ratio of ∼3. This is possible due to the interaction with carbonation and the formation of other iron containing phases. Here, the proposed calcium and chemical looping combustion using C2F was...
Laser-induced grating spectroscopy (LIGS) is applied, for the first time, to a swirling nonpremixed hydrogen–air flame in a high-pressure combustion facility. A portable LIGS unit is used to probe 35 different axial and radial locations in the flame, and a new conditioned processing approach based on laminar flame simulation is introduced t...
The structure of hydrogen-enriched methane-air flames in a Bunsen burner at low turbulence is investigated using OH planar laser-induced fluorescence (PLIF). Three flames are investigated at identical unstretched laminar flame speeds and turbulence conditions, while hydrogen enrichment is varied up to 70% by volume. An increase in global flame cons...
Hydrogen is a promising zero-carbon fuel for decarbonized energy and transportation sectors. While carbon emission is not a concern for hydrogen combustion, its higher adiabatic flame temperature poses challenges of mitigating thermal NOx emissions. The wide flammability limits of hydrogen allow a fuel-lean operation, which can reduce NOx emissions...
The oxidation of small particles (size 200 μm) of char from oak has been studied, by adding a small batch of them to an electrically heated bed of inert, silica sand, fluidised by mixtures of O2 and N2. The concentrations of CO, CO2, and O2, in the off-gases from the bed were continuously monitored, enabling the rate of combustion and also the frac...
We analyze 3D reconstructed surfaces based on previously reported high frequency measurements of flame edge location across expanding flames using Mie scatter. For the first time, principal curvatures of flame surfaces are estimated from eigenvalues of the second fundamental forms of the reconstructed surfaces, allowing the determination of the sta...
The mechanism of propagation close to flame-flame interaction events is analysed using direct numerical simulation of a turbulent premixed methane-air flame. Four canonical local topologies arising from flame-flame interaction are identified in the vicinity of critical points. These correspond to reactant pocket, tunnel closure, tunnel formation an...
The mechanism of flame stabilisation using nanosecond repetitively pulsed (NRP) plasma discharges in a turbulent, premixed methane-air flame at high velocities was investigated, focusing on the lean extinction limits. In contrast to the majority of the existing studies that considered NRP discharges as an assistance to conventional stabilisers, her...
The mechanism of flame front propagation in NH3/air and NH3/H2/air steady, laminar premixed flames is examined. Since the process is characterised by a state of chemical non-equilibrium, the analysis focuses on the explosive mode that is introduced by chemical kinetics. The chemistry expressed in this mode is the one that tends to lead the system a...
