An improved particle generator based on electrodynamic powder fluidization is proposed and constructedfor investigating single metal particle’s combustion. The designed setup is able to generate a single metalparticle moving upward with a well controlled velocity and trajectory and ignite it at near-uniform conditionsby an infrared laser beam with flattened elliptical beam profile. Mechanically sieved narrow fractionsof spherical iron particles with mean sizes in the range of around 26–54 μm were used in experiments.Particles burned in O_2 /N_2 mixtures with oxygen content varying from 21 to 36. Particle’s trajectories,velocities, and arbitrary radiant intensities were measured by taking images with a high-speedcamera and processing them with an in-house developed data processing program. Two characteristictimes associated with particle combustion were measured: 1) total duration of high-temperature phase( t_(tot) ) and 2) time to the maximum brightness ( t_(max) ). The results show that t_(tot) and t_(max) can be described by a d~n -law with 1.57 approx< n approx< 1.72 and 1.46 approx< n approx< 1.60 , respectively. The effect of oxygen concentrationon t_(tot) , t_(max) , and t_(dec) = t_(tot) ? t_(max) was analyzed for selected particle sizes of 30, 40, and 50 μm. It wasfound that t max ∝ ( 1 /X_(O2))~n with 1.04 approx< n approx< 1 . 18 is almost linearly proportional to 1 /X_(O2) , while t_(dec) showsa very weak dependency on the oxygen concentration at 26–36. This can be explained by the idea thatthe overall combustion process of iron is controlled by first external and then internal diffusion of oxygenowing to the saturation of oxygen on the particle surface.
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