<title>Metal Combustion In High Pressure Oxygen Atmosphere: Detailed Observation Of Burning Region Behavior By Using High Speed Photography</title>

Abstract

AbstractDetailed process of upward fire spread along a mild steel cylinder in high pressureoxygen has been studied by using high speed photography. Fire spread experiments were con-ducted in a cylindrical, high pressure oxygen chamber of a capacity of about 2.5x107 mm3.The movement of a molten mass attached to the bottom end of a burning steel cylinder andthat of a molten mass droplet detached from the bottom end were recorded by a 16 mm or 35 mmhigh speed cinecamera and analyzed.By analyzing the oscillatory behavior of the molten mass droplet, its main component wasinferred to be iron oxide. The local spread rate fluctuation was observed during a periodof the overall cyclic behavior. Based on the location of the observed high luminosityregion and surface flow of the molten mass, convection was inferred to be a dominant mode ofheat transfer at the molten -solid boundary and the fluctuation of the local spread rate wassupposed to be attributable to the non -uniformity of the convective heat transfer at themolten -solid boundary.IntroductionAn appropriate assessment of structural metal fire hazards is needed to prevent seriousaccidents of various plants and rocket motors in which high pressure oxygen is used.1 -2 Forsuch an assessment, sufficient and correct knowledge of the burning characteristics ofstructural metals would be required, and several studies have been carried on this subject.