Finger Formation during Combustion of Granular Mixture Zr + 0.5C in Inert Gas Flow

A new mode of combustion of granular mixtures Zr + 0.5C in a co-current argon flow with the formation of a finger-like front instability was discovered. The observed phenomena were explained under the assumption of a decrease in the permeability of synthesis products due to significant shrinkage of the sample in the longitudinal direction, which prevented the filtration of argon through the products. Redirection of the gas flow into the gap between the granules and the side surface of the cylindrical reactor contributed to the formation of a finger. It was shown that a decrease in the sample size in the longitudinal direction is provided by the pressure drop of argon, and a decrease in the cross-section occurs under the action of surface tension forces due to a transverse temperature gradient.