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Electro Thermal ExplosionPopov Konstantin Viktorovich researcher , Ph.D. E-mail: kostya@ism.ac.ru |
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ElectroThermal Explosion (ETE) is practically unique
experimental method, enabling to investigate a mechanism and
a kinetic of high-temperature high-speed exothermic reactions in
heterogeneous condensed systems, at temperatures up to 4000 K
with characteristic conversion times less than 1 ms. In the
basis ETE is heating of reactable sample by direct passing of
an electrical current through it with instant interruption of
an electric heating at the moment of a self-ignition begins and
the optical registration in a time of sample surface temperature.
The adiabatic self-heating of a sample provides a space uniformity
passing of the reaction and enables with quantitative completeness
to calculate the kinetic parameters from an experimental thermograms.
Technique The ElectroThermal Explosion method permits to raise the top temperature border up to significances of the order 4000 K and to register speed of reactions with characteristic conversion times up to 0.1 ms, i.e. to study of the kinetic in all temperature-time interval, presenting interest for theoretical and applied problems of a combusion and an explosion. And on width of a working temperature interval, and on maximum speed of registered reactions in condensed environments the ETE method essentially surpasses (in temperatures - on thousands of degrees, in times - on the orders) all other kinetic techniques, in which the researched chemical conversion in a heterogeneous condensed mix is executed in space isothermic conditions. The application of model samples, rolled - up from foils, permits to save a surface of reactant contact up to the moment of welding a more refractory component of a system. By using simple models the disolution constants in systems Ni-Al and Ti-Al were quantitatively calculate. For systems with high exothermic reaction, but with low conductivity, the dilution method of a reacting mix by well conducting inert for registration of kinetic and macrokinetic parameters was used. The works with thermit systems, such as Ti-NiO, Ti-MoO3 and Ti-Fe2O3 were conducted. Setup The automated experimental setup for research of high-speed reactions by ElectroThermal Explosion method is created. The software for realization of experiment, analysis and data processing experimental ETE-thermograms is developed. The method is testing on powder samples (Ti + C, Ta + C, Ti + B, Ti + Ni, Ni + Al and etc.), and on model foil samples (Ni + Ti, Ti + Al, Ni + Al). Application The development of the combusion theory of such systems, as thermit - on the one hand and SHS objects (at first - system, capable to so-called gassless combusion) - with other hand, testifies that a main problem is absence of reliable data on macrokinetic (kinetic) of high-speed high-temperature reactions in these systems. In works of Merzhanov, Manelis, Zenin, Maltsev and their employees the valuable information on a mechanism and kinetic of high-speed high-temperature reactions was received from data on measurement of temperature fields and combusion speeds of condensed systems. However, for account of kinetic parameters by these methods are necessary a priori of the item of information on adequacy to real processes of mathematical models used by authors. Such data, as a rule, are absent. ETE is today, as appear, unique experimental method, enabling without of the a priori assumptions of a mechanism of interaction with quantitative completeness to calculate the macrokinetic characteristics of processes in extremely wide interval of change of working parameters: temperatures (up to 4000 K) and conversion times (less than 1 ms). The data, received the last 3-5 years with help ETE, were used for:
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