Mechanism of Titanium Ignition during Fracture in Oxygen
B. I. Bolobov
St. Petersburg Mining University, St. Petersburg, 199106 Russia
Keywords: критическое давление возгорания, кислород, титан, фрагмент разрушения, коэффициент теплоотдачи, critical ignition pressure, oxygen, titanium, fracture fragment, heat transfer coefficient
Abstract
This work demonstrates that the heating of fracture fragments of rods made of VT1-0 commercial titanium and its alloys OT4-1 and PT3V in gaseous oxygen at a pressure p O2, which is accepted in this paper and in the works of other researchers as critical pressure p *, only leads to melting of individual regions of the formed juvenile surface, which differ from each other only by obstructed heat sink, and the metalì-oxygen interaction does not transfer into combustion. However, this interaction does transfer into combustion during which the bulk of the metal burns out at a slightly higher pressure p **, which can be calculated from the thermal explosion equation for temperature T * that is equal to the melting point of titanium, with account for the dissociative absorption of oxygen molecules on the melt surface and the heat exchange coefficient corresponding to the case where the heat is transferred from the melt hemisphere to the semibounded solid body.
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