Combustion of spherical titanium aglomerates in air. III. Movement of agglomerates and the effect of airflow velocity on nanosized combustion products and burning time
Abstract:
The combustion of monodisperse titanium particles with a characteristic size of 38 and 320 $\mu$m moving in air has been studied. Pyrotechnic samples generating monodisperse particles were burned in a chamber with a nozzle to impart initial velocity to burning particles. Particles were accelerated by the combustion gas flow from the nozzle. The maximum path-averaged particle velocity relative to the ambient air reached 7.9 m/s. Combustion of moving particles was carried out in a quartz tube 2 m long. At the end of the combustion, combustion products – oxide aerosol – were sampled from the tube using a thermophoretic precipitator. The size distribution function of nanometer-sized spherule particles was determined by processing electron micrographs of samples. The velocity and burning time of the burning particles were determined by video recording at a velocity of 300 frame/s. It was found that increasing the speed of motion of agglomerate particles with a diameter of 320 $\mu$m relative to the gas from 0.9 to 7.9 m/s leads to a decrease in the size of the spherules from 28 to 19 nm and to a decrease in the burning time from 0.45 to 0.26 s.
Keywords:titanium particle, titanium agglomerate, combustion, particle velocity, characteristic time of fragmentation, burning time, condensed combustion products, nanosized oxide spherule particles, size distribution.
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