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Lepikhin S.A.,Birsk State Social and Pedagogical Academy | Galimzyanov M.N.,Russian Academy of Sciences | Gimaltdinov I.K.,Sterlitamak State Pedagogical Academy
High Temperature | Year: 2010

Special features are investigated of the initiation of detonation waves in chemically active bubble media located in channels of variable cross section. It is found that, depending on the initial volume content of combustible mixture, the detonation in convergent channels may proceed with the emergence of one or two detonation solitons. The possibility of the emergence of a stable detonation wave upon reflection from the channel bottom is demonstrated in channels with closed bottom. Also demonstrated is the possibility of initiation of detonation upon reflection of the wave from the region of "pure" liquid. Depending on the amplitude of initiating wave and of the initial volume content of bubbles, a map of solutions is constructed which illustrates the modes of the process of detonation in the considered channels. © 2010 Pleiades Publishing, Ltd. Source

Shagapov V.Sh.,Russian Academy of Sciences | Nurislamov O.R.,Birsk State Social and Pedagogical Academy
High Temperature | Year: 2010

A classical model boundary layer problem is considered for the flow of liquid past a plate in view of injection of a vapor-gas mixture from its surface. The obtained self-similar solutions enable one to estimate the typical values of thickness of the vapor-gas layer, the value of heat-transfer coefficient as a function of temperature of liquid, intensity of injection and composition of mixture being injected, and the velocity of flow past the plate. In addition, the problem is considered of reducing the hydrodynamic drag owing to vapor and vapor-gas "lubrication" because of boiling of liquid and injection of vapor-gas mixture from the plate surface. The possibility is analyzed of the emergence of vapor film due to viscous friction forces in the case where the liquid is in the vicinity of the boiling point. © 2010 Pleiades Publishing, Ltd. Source

Shagapov V.Sh.,Russian Academy of Sciences | Tazetdinov B.I.,Birsk State Social and Pedagogical Academy
Theoretical Foundations of Chemical Engineering | Year: 2013

Methane hydrate decomposition at atmospheric pressure in the overheated state relative to the equilibrium temperature (T S = 193 K) at positive (T 0 > 273 K) and negative (T 0 < 273 K) temperatures is discussed with reference to available experimental data. Two temperature ranges (193 K < T 0 < 240 K and 240 K ≤ T 0 < 273 K) arte distinguished at negative temperatures, and one temperature range (T 0 > 273 K) at positive temperatures. For the lower range of negative temperatures, it is accepted in the construction of the theoretical model that the major factors determining the intensity of gas hydrate decomposition into ice and gas are Arrhenius-type kinetics and conductive heat transfer. Two schemes, namely, frontal and bulk ones are considered. For the upper range of negative temperatures, where an anomalous preservation effect is observed in experiments, it is assumed in the theoretical model that the release of the gas from the hydrate is controlled by the diffusion mechanism of gas transport through the solid phase or through the surface ice crust. For the positive temperatures, it is accepted that the decomposition rate is determined by the heat flux through the draining water film that has resulted from hydrate decomposition. Calculations have been carried out for different initial and boundary temperatures, and the results of the calculations have been analyzed and have been compared to available experimental data. © 2013 Pleiades Publishing, Ltd. Source

Shagieva F.I.,Birsk State Social and Pedagogical Academy | Galeeva G.Ya.,Bashkir State University
High Temperature | Year: 2010

The problem is considered on the injection of moist steam into a porous medium saturated in the initial state with gas and paraffin. Self-similar solutions describing hydrodynamic and temperature fields are constructed assuming that the intensity of injection is limited by the hydraulic drag of water plug formed because of condensation of vapor. Analysis is made of the effect of heat consumption on the process of development of heated zones during the melting of paraffin. © 2010 Pleiades Publishing, Ltd. Source

Amstislavskii Y.E.,Birsk State Social and Pedagogical Academy
Optics and Spectroscopy (English translation of Optika i Spektroskopiya) | Year: 2011

An autocollimation system with an illuminated circular entrance aperture located in the front focal plane of a lens L is considered. In the middle between and L, a transparent plate a few millimeters thick is placed at an angle of i0 = 45° to the axis of the system, and, near the rear focal plane of the lens L, a plane reflecting mirror is placed. The plate divides the primary beam into parts during its propagation both forward and backward (after the reflection from the mirror). This ensures the formation of derivative beams that propagate toward an ocular and that are overlapped in the region of spatially separated images S0, S1, and S 2. The possibility of formation of a high-contrast system of first-order two-beam interference fringes in the region of S 2 is discussed. Conditions for achieving this result are also discussed. © Pleiades Publishing, Ltd., 2011. Source

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