Effect of orientation on the inflammation of PMMA by laser radiation

The effect of heat and mass transfer on the conditions of appearance of a flame depending on the orientation of the polymer surface with respect to the direction of gravity is examined. The dependence of the delay time of inflammation of polymethyl methacrylate (PMMA) on the angle of orientation for different values of the heat flux is shown. The effect of orientation on inflammation must also be manifested in other materials capable of diffusion combustion. Each material, however, has its own range of irradiation flux densities. As is evident, when the critical angle is exceeded, the flow of gaseous products presses against the surface, and the thickness of the flow changes markedly.