COMBUSTION CHARACTERISTICS OF MONODISPERSE TITANIUM PARTICLES FAST MOVING IN AIR

摘要

A study is made of the combustion of monodisperse titanium particles of a characteristic size of 38 and 320 micron upon their movement in air. For the particles to move rapidly, pyrotechnic compositions generating monodisperse particles were burnt in a chamber with a nozzle. The particles gathered speed in a jet of the gaseous products of sample combustion outflowing from the nozzle. The maximal, trajectory-mean velocity of particle movement relative to gas was 7.9 m/s. The moving particles were burnt in a quartz tube 218 cm long. After combustion, the products, i.e., oxide aerosol particles, were collected from the tube using a thermophoretic precipitator. The size-distribution functions of nano-sized particles (spherules) were determined by processing electron-microscopic images. Video recording at a rate of 300 fps was used to characterize the velocity of burning particles and to determine their combustion times. It has been established that an increase in the velocity of particle movement relative to gas leads to the decrease in both spherule size and , combustion time.