In order to reduce the computational cost of flame simulations, several methods have been developed during last decades, which simplify description reaction kinetics. Most these are based on partial-equilibrium and steady-state assumptions, assuming that most chemical processes a much smaller time scale than flow scale. These however, give poor approximations in 'colder' regions flame, where transport also important. The method presented here, can be considered as combination two approaches...

Abstract A simple and accurate method is presented to determine the flame temperature adiabatic burning velocity of laminar premixed flat flames, using a specially constructed burner. The heat loss determined from measurement profile burner plate. found when plate uniform, implying that net zero. Several methods are thermal conductivity results for methane/air mixtures compared with experimental data in literature one-dimensional calculations, close agreement found. particularly useful...

Abstract A simple analysis and measurements are presented, which show that adiabatic premixed laminar flames can be stabilized on a flat flame burner, especially designed for this purpose. The physical properties of these identical to those freely propagating flames. state accomplished in practice when the burner plate temperature is well above unburnt mixture. net heat loss zero (i.e. adiabatic) measured radial profile uniform. These particularly suitable comparison with theoretical or...

The combustion behavior of single laser-ignited iron particles is investigated. Transient particle radiant intensities at 850 nm and 950 are measured by post-processing recorded high-speed camera images using an in-house developed tracking program. Then, the time-resolved temperature obtained based on two-color pyrometry. A plateau-like stage shortly after ignition repeatedly observed, identified as melting estimated time. Besides, abrupt brightness jump near end observed for most burning...

An improved particle generator based on electrodynamic powder fluidization is proposed and constructed for investigating single metal particle's combustion. The designed setup able to generate a moving upward with well controlled velocity trajectory ignite it at near-uniform conditions by an infrared laser beam flattened elliptical profile. Mechanically sieved narrow fractions of spherical iron particles mean sizes in the range around 26–54 μm were used experiments. Particles burned O2/N2...

We present a numerical study of the combustion single iron particles in an O2–N2 atmosphere. By resolving full boundary layer, mass and heat transfer are accurately modeled, including Stefan flow. Only conversion Fe to FeO is taken into account evaporation implemented investigate formation nano-sized iron-oxides products. Temperature- composition-dependent capacity density used phase transitions from solid liquid (and vice-versa) accounted for by apparent method. The model validated...

To further our understanding of iron particle combustion, especially in the liquid state, insitu optical measurements are performed for size evolution and temperature laser-ignited particles a narrow range around 45–55μ m. The is monitored by high-speed shadowgraphy system, probed using two-color pyrometer synchronized with system. Before reaches peak temperature, its diameter grows linearly elapsed time. Near three types behavior detected, namely, smooth transition, micro-explosion, rapid...

In the present study, a novel and initiative approach towards self-sustainable metal combustion burner called "Metal Cyclonic Combustor (MC2)" is introduced. The results show that self–sustained iron flame can be established inside MC2 under normal air conditions (21% O2), even at very low oxygen concentrations (∼ 10% O2) for overall equivalence ratios 0.2), without any assisting extra heat sources. However, demonstrate proper preheating level corresponding to concentration still guarantee...

Flame propagation of iron powder in air is numerically studied. The present work introduces a chemical equilibrium model, which allows detailed representation the combustion products, phase transitions and thermodynamics condensed phase. First, to validate single particle, numerical laser ignited particle studies are performed compared experiments, where very good agreement obtained. A second series simulations on laminar flames iron/air mixtures for wide range equivalence ratios (ϕ=...

Molecular dynamics (MD) simulations are performed to investigate the thermal and mass accommodation coefficients (TAC MAC, respectively) for combination of iron(-oxide) air. The obtained values TAC MAC then used in a point-particle Knudsen model effect chemisorption transition regime on combustion behavior (fine) iron particles. interactions $\mathrm{Fe}$ with $\mathrm{N_2}$ $\mathrm{Fe_xO_y}$ $\mathrm{O_2}$ is investigated different surface temperatures, while coefficient oxygen initial...

We present temperature histories of individual combusting metal particles using hyperspectral pyrometry. This method gives an increase in accuracy over traditionally used two- or three-color pyrometry, while maintaining temporal and spatial resolution. Temperatures can be determined between 1800 to >3000 K with a precision typically <1%. It is shown that the maximum burning iron increases from 2760 2840 increasing mean particle size 32 54 μm air 21 % oxygen. The relatively high temperatures...

This work shows the evolution of particle properties for cyclic combustionreduction.• These initial experiments resulted in a promising average storage efficiency 86%.• The suggest that powder can be utilized effectively process.

Abstract In the recently introduced flamelet-generated manifold (FGM) method ideas of and flamelet approach are combined: a is constructed using one-dimensional (1D) flamelets. this paper effect flame stretch on accuracy FGM investigated. order to isolate stretch, premixed methane/air counterflow flames simulated. case unit Lewis numbers, 1D sufficient model main effects stretch. A with two progress variables reproduces results computed detailed kinetics almost exactly. When non-unit numbers...