In powder industry, automation for continuous production is frequently employed. Owing to particulate characteristics, suspended nano-metallic powders in automatic transportation have been commonly encountered. The nano-metallic powders in gas phase satisfy the requirements of dust explosion by appropriate ignition conditions. Sometimes, transporting pipeline and dust-collecting equipment is connected, rendering large casualties and losses by detonation. Following the development of science and technology, nano-metallic aerosols become smaller and require smaller collision energy, yielding stronger explosive effect. When the attraction force among nanoparticles is larger than the repulsion force, the nanometallic powders can be stably suspended in gas. When the reverse is true, the particles coagulate and the explosion possibility increases.
The purpose of the present research is to analyze thermal properties and
explosion characteristics of nano-metallic powders in gas phase. Especially, effect of particulate volume fraction in a system will studied experimentally and theoretically.
The research demonstrated larger turbulence velocity to be able to make uniform dust cloud, causes the explosion pressure and the ratio of pressure rise increase. When transports by 135 degree angle, may decrease dust collision and suppression dust agglutination phenomenon. The dust cause the explosion pressure, the ratio of pressure rise and the explosion damage degree is Al > Ti > Fe. Minimum ignition energy of three kind of nano-metal dust of transport by the air is low than 1 mJ and transport by nitrogen is low than 1 mJ for titanium, 30 mJ for iron and 3 mJ for aluminite.