Effect of tube diameter on homogeneous gas flame propagation limits

This study examines the effect of tube diameter on flame propagation limits under conditions where convective factors can be expected to manifest themselves. Gives special attention to boundary conditions and the direction of flame propagation. Discusses flame propagation in the direction of gravity and against gravity. Suggests that the observed convective peculiarities of the flame hearth in the early stages of combustion (deformation and floating up of the hearth) indicate the strong effect of free convection on the flame propagation limits. The results of the experiments also demonstrate the presence of ''tube'' effects, i.e., peculiarities related to the limitation of space by the tube walls. In contrast to free space, the flame velocity, flame from surface area, and heat liberation in tubes are dependent on diameter.