COMBUSTION CHARACTERISTICS OF PYROTECHNIC MIXTURES CONTAINING TITANIUM

摘要

The combustion of CI-free propellants with various (15-29 %) Ti loading is studied at atmospheric pressure. The burning rate and characteristics of the condensed combustion products (CCP) are determined. Mass size distribution of CCP particles is measured in entire range of sizes. To determine characteristics of nanoparticles in CCP, the original technique is used based on probe sampling from the flame with subsequent measurements by diffusion aerosol spectrometer. The morphology and sizes of sampled by thermophoretic precipitator aggregates composing of nanoparticles are examined by electron microscope. It is revealed that original titanium particles agglomerate in the combustion wave even at relatively low (15 %) metal loading that leads to formation of slag residue. The burning rate increases with Ti content in propellant, simultaneously the mass of slag residue increases reaching 25 % of propellant mass at 29 % Ti loading, and the completeness of metal combustion decreases. The yield of Ti oxide smoke is about few percent of Ti mass in propellant. Mean count diameter of primary particles of metal oxide smoke amounts 23-32 nm that corresponds to the value if specific surface 30-40 m~2/g. According to X-Ray diffraction data the smoke particles are presented by TiO_2 particles of different crystal modifications.