V. K. Smolyakov

Thermal explosion in mechanically activated heterogeneous systems

A mathematical model for thermal explosion in a mechanically activated heterogeneous system was constructed and tested. The model includes equations of thermal balance, chemical transformation, and dynamics of excess energy in condensed substances. The model was analyzed by analytical methods. Relations determining the characteristics of thermal explosion were obtained. The accuracy of analytical estimates was verified by numerical simulation.

Impact of Structural Factors on Unsteady Combustion Modes of Gasless Systems

Based on the two‐temperature, two‐velocity time‐dependent model of gasless combustion, taking into account structural transformations related to the force action of the gas filtering in the pores and vitrification and volume variation of the condensed phase during the chemical transformation, self‐oscillatory combustion modes are studied. Structural transformations are shown to have a pronounced effect on the propagation pattern of combustion waves and can either stabilize or destabilize combustion. The major structural parameters appreciably affecting combustion‐wave stability are the initial porosity, particle size, and pressure.

Unsteady Combustion Regimes of Gasless Systems with a Low-Melting Inert Component

The paper studied the effect of temperature and heats of melting of an inert low-melting component of a mixture and its quantity on the regularities of ignition and unsteady combustion regimes of gasless systems.

On the theory of self-propagating high-temperature synthesis in layered systems

The formation of a composite material during gasless combustion of a layer stack is considered. Combustion of the external donor layers causes melting of the internal inert layer, after which the melt flows into the pores of the skeleton. The flowing depth, determining the structure of the composite material depends on the pore size, surface tension, phase transition parameters, and temperature changes.

Effects of boundary kinetics in stationary combustion in a gas-free system

This article presents a qualitative study of the effects of the boundary reactions on the speed of the combustion wave and the propagation laws. The analysis is performed for stationary combustion in a model heterogeneous system consisting of ordered layers of the reacting components. Neglects the difusion of the material in the direction of combustion-wave propagation and assumes that in accordance with the phase diagram for the A-B system the reagents interact only to form a single layer of the product AB. The propagation of the combustion wave throughout the range in the relevant parameters is characterized by a reaction zone with a narrow temperature distribution.

Gasless combustion of a system of thermally coupled layers

This paper presents the numerical simulation of gasless combustion of a sample as a combination of thermally coupled flat layers consisting of two different chemical compounds, which represent the model of a chemical furnace. The critical combustion conditions are established, depending on the volume ratio of mixtures in the sample or the content of reaction products. The time, velocity, and combustion modes of the layer composition are determined, depending on the volume content of the mixtures, the thickness, and the number of layers. The combustion wave propagation in view of “homogenization” of the sample with layer thickness decreasing at a fixed concentration of the components is considered.

Modeling the synthesis of mechanocomposites in binary systems

A mathematical model was constructed for the nonisothermal synthesis of precursors in a mixture of two reagents during mechanical treatment in mills. The model takes into account the grinding and agglomeration of particles, the formation of a reaction interface, the kinetics of chemical transformation, the change in the excess energy in the components of the mixture and temperature.

On the Theory of Electrical Phenomena in Combustion of Heterogeneous Systems with Condensed Products

The effect of the electromotive force arising in combustion of heterogeneous systems with condensed products is explained. A convective mechanism of arising regions with different charge densities due to charge transfer by the gas filtered in the pores is formulated on the basis of the developed physical concepts, estimates, and analysis of experimental data. Key words: combustion, electron emission, filtration, electromotive force.

Inert Additive Melting in a Gasless Combustion Wave

The effect of melting of an inert additive on the pattern of gasless combustion is analyzed for the case of a single-stage reaction. Stationary combustion regimes with a phase transition are studied analytically and numerically. The phase transition is shown to manifest itself differently in the dependences of the combustion velocity on the amount of the inert additive and the initial temperature. Combustion regimes are analyzed, where the front velocity in the model considered is independent of the inert additive amount. Making use of such regimes in studying the effect of structural factors on combustion is discussed. Key words: gasless combustion, low-melting inert component, phase transition.

Effect of the phase transition on three-dimensional unstable regimes of gasless combustion

The thermal effect of the phase transition on unstable regimes of gasless combustion is numerically studied within the framework of the model of solid flame combustion of a cylindrical sample. The closer the phase transition temperature to the burning temperature, the more pronounced the effect of the phase transition on the combustion character. In this case, the combustion front surface is noticeably smoothed owing to reduction of temperature gradient values. A relationship between the change in the combustion modes considered in the study and the change in the phase transition parameters is found. An unsteady periodic symmetric mode of combustion with ring-shaped trajectories of motion of combustion sites over the side surface is obtained.