Effect of a Ti+C Granule Size on Combustion in a Nitrogen Flow
B. S. Seplyarskii, R. A. Kochetkov, T. G. Lisina, N. I. Abzalov
Merzhanov Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Chernogolovka, 142432 Russia
Keywords: SHS, Ti+C, granule size, cocurrent gas flow, convective combustion, microheterogeneous model
Abstract
Dependence of the combustion of a Ti + C granular charge on a granule size is experimentally studied.It is revealed that the burning rate of a granular mixture of all fractions used in the work is higher than the burning rate of a bulk-density powder mixture. It is shown that, with a decrease in the granule size, the burning rate of the charge in the absence of gas decreases due to an increase in the number of boundaries between the granules per unit length of the sample. A strong influence of the nitrogen flow on the burning rate of both large and small granules is established. It is shown that, in contrast to small granules, an increase in the nitrogen flow rate of large granules up to 600 l/h leads to a transition to convective combustion. The studies performed indicate that, despite the structural analogy between mechanically activated and granular mixtures, the relationship between the combustion time and the front transition time in granular mixtures is completely different. This means that the combustion of granular mixtures even in the absence of a gas flow cannot be explained within the framework of a microheterogeneous model.
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