Combustion of large monolithic titanium particles in air. I. Experimental techniques, burning time and fragmentation modes

A technique for obtaining large burning monolithic titanium particles is described. The combustion of particles with a diameter of 120–540 $\mu$m in free fall in air at atmospheric pressure is investigated. The burning time and the characteristic time of the beginning and end of fragmentation as a function of particle diameter are determined by processing video recordings of combustion of more than 250 particles. Two fragmentation modes are described. It is found that their occurrence depends on the diameter of the burning particle. The boundary particle size separating the modes is determined. It is shown that the fragmentation regularities and characteristic times for titanium agglomerates and monolithic particles of the indicated sizes differ slightly.