Macrokinetics for Macrostructure Forming of a Product in Self-Propagating High-Temperature Synthesis

Abstract:

A heterogeneous model for ignition and combustion of cylindrical free-gas samples with a gas-permeable and impermeable surface, including the description of structural and phase transformations is formulated. The effective method for numerical model research, taking into account a zonal structure of combustion wave is offered. Dynamics of porous structure forming of products from a stage of ignition up to the steady mode of exothermal reaction front propagation is considered. The calculated stationary combustion rate and elongation of a burned specimen versus its diameter, particle size of a fusible component, initial porosity and pressure of inert gas are received. Experimental data are qualitatively compared with calculated ones. The change in characteristics of combustion wave in a non-stationary mode is analyzed. The structural oscillations resulting in lamination of a porous specimen in a zone of synthesis products in a self-oscillatory combustion mode are found out. The factors, which are the reason for structural oscillations occurrence are determined. Modeling for mechanical compression of a sample shows that a stabilizing effect on the process of combustion consists of additional compensation of loosening forces.

• Periodical: Advances in Science and Technology (Volume 63)
• Pages: 222-227
• DOI: https://doi.org/10.4028/www.scientific.net/AST.63.222
• Online since: October 2010
• Authors: Vadim Prokofiev, Victor Smolyakov
• Keywords: Macrostructural Transformation, Self-Oscillatory Combustion, Self-Propagation High-Temperature Synthesis (SHS)

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