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1
Content available remote Dispersed phase breakup at emulsion boiling
100%
Pavlenko A. M.
Journal of New Technologies in Environmental Science
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2017
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tom Vol. 1, nr 4
171--180
EN
The processes of breakup and deformation of the dispersed phase is considered by many researchers [1-7], but these data require further study, which will determine the most profitable in economic and environmental terms parameters for their implementation. The classical theory of drops deformation and destruction depending on the turbulence level belongs to [3]. He considered this process as a result of realization of a large number of random events and on the basis of the probability theory he obtained the logarithmic drops distribution basing on the drops size. In general, the problem of breakup of liquid dispersions in a continuous medium is divided into two [3-5]: liquid droplets breakup in the emulsions and gas streams. When considering these processes the drop stability to the effecting forces is important, as these forces tend to destroy it. In most cases presented in references calculations are based on Bond and Weber criteria [1-4, 9], i.e. they consider only the Rayleigh-Taylor and Kelvin-Helmholtz instability, which are more specific for emulsification or destabilization of dispersed media. The droplets breakup and deformation processes while moving in a liquid are described in [3-5]. However, the existing models do not consider the breakup process of the secondary fluid with taking into account the formation of vapor layer at the boundary between the two phases as well as the force interaction regarding several simultaneously boiling particles of dispersed phase [8, 10, 11]. The vapor cavity formation is assumed to be homogeneous and only the maximum dynamic effects are considered, while the destruction of the dispersed phase can occur at any time due to the fact that the hydrodynamic environment even in the vicinity of two growing bubbles is undefined and if a particle of the dispersed phase is at some distance from these bubbles (or between them at a certain distance), then the effect of the particle breakup will be on reaching the maximum force that will exceed a critical value, calculated by Weber or Bond criteria, but it won’t necessarily be equal to maximum which can act in this system. The process becomes even more complicated and requires further study if we consider the breakup process of dispersed phase which begins to boil by itself.
2
Content available remote Mathematical solution to the problem of obtaining massive amorphous structures
63%
Pavlenko A. , Pavlenko A. M.
Journal of New Technologies in Environmental Science
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2018
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tom Vol. 2, nr 3
134--139
EN
This article proposes a mathematical formulation of the problem of casting a metal in a water-cooled mold. The model includes a heat conduction equation that describes thermal phenomena under appropriate boundary conditions.
3
Content available remote Destruction processes of oil films of emulsion environment
63%
Klimov R. A. , Pavlenko A. M.
Journal of New Technologies in Environmental Science
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2018
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tom Vol. 2, nr 2
75--83
EN
Most of the methods aimed at studying the dynamics of growth of vapor bubbles which occur either in the liquid volume or on a superheated surface [1-3]. A peculiarity of emulsion media boiling is that the formation of a vapor phase occurs on the surface of liquid interface if one liquid (for example, oil) is a superficially active substance or in the emulsion there is a superficially active substance (in multicomponent emulsions), which is based on a decrease in the interfacial tension at the interface between the dispersive medium (water) and the dispersion phase (oil) [1, 3-6]. Experimental data [1, 3] indicate that the process of a new phase (vapor) formation is initiated by an internal thermal impact on the surface of the oil particles. Thus, for example, with a sudden pressure decay, the preheated emulsion will be in the supersaturation state of the thermolabile-water phase (the water is superheated against the saturation temperature at a given pressure), i.e. it will contain an excessive amount of heat [7-10]. This heat excess is expended on the work of vapor layer formation and further vaporization. The effect of oil films is ambiguous: on the one hand, when heated, they play the role of thermal resistance, thus, slowing down the heating process; on the other hand, they are the heat carriers which can be used for the formation and growth of the vapor phase and also they are superficially active substance, which contributes to achieving lower water supersaturation temperatures, i.e. early boiling [5]. The consideration of oil thermal effect plays an important role when regarding heat and mass transfer processes during the boiling of emulsion media. Theoretical description and analysis of heat and mass exchange processes in emulsions, associated with the presence of oil and oil films, allows us to study more in detail the process itself, as well as to offer optimal parameters and characteristics for the processes of obtaining and processing a fine emulsion.
4
Content available remote Investigation of the process of pore formation based materials hydrosilicates
63%
Pavlenko A. M. , Cheilytko A.
Journal of New Technologies in Environmental Science
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2018
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tom Vol. 2, nr 4
174--182
EN
Research porosity thermal insulation of refractory materials is the important task of power engineering, because the thermal conductivity of porous materials depends on the shape and especially location of pore. Analytical review of existing technologies shows that research in this area focused on the study of a process separately and generalized theories is not sufficient to clear analysis and model building process heat mass transfer of alumina porous material. Experimental and generalization of the characteristics of heat and mass transfer in porous materials that swelling is actual scientific problem. In this paper analyzes the different composition of aluminous minerals, aluminum effect of additives on the formation of pores, as well as the influence of various impurities on the thermal conductivity of the material. The effect of temperature on the thermal conductivity of porous materials.
5
Content available Thermal insulation materials with porous structure
63%
Pavlenko A. M. , Koshlak H. V.
Structure and Environment
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2018
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tom Vol. 10, no. 3
258--265
EN
The raw mix of silica-containing technogenic component – fly ash of thermal power plants - and the methods of preparing waterproof porous thermal insulating materials of extended application on its base according to the powder low-temperature technology has been developed using multifunctional properties of soluble glass as: a) a binding component; b) blowing agent; c) the raw mix hardening rate regulator. The physical and chemical, technological aspects of obtaining and using the suggested alkaline-silicate compositions have been considered.
PL
W artykule przedstawiono zagadnienie produkcji wodoodpornych materiałów termoizolacyjnych przy wykorzystaniu mieszanek zawierających krzem i popiół lotny, pochodzący z elektrowni w oparciu o niskotemperaturową technologię proszkową. Opiera się ona o wykorzystanie szerokich właściwości szkła wodnego, tj. jako: a) element łączący, b) element spulchniający, c) regulator twardnienia. W pracy rozpatrzono fizyczno-chemiczne i technologiczne aspekty wytworzenia i wykorzystania tego typu kompozytów.
6
Content available remote Porous structures and their effect on thermophysical properties of thermal protection elements
51%
Pavlenko A. M. , Cheilytko A. , Ilin S.
Journal of New Technologies in Environmental Science
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2018
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tom Vol. 2, nr 3
125--133
EN
The improvement of the thermal insulating material thermophysical characteristics of the thermal protection elements by studying the porous structure is a promising direction of research. The article describes the effects of the porosity and coupling of the porous structure on the thermophysical characteristics of thermal insulating materials. The article uses standard systematized techniques and instruments of scientific research applied in thermophysics. The research methodology of highly-porous material thermophysical properties is based on performance of empirical laboratory investigations of the samples obtained.
7
Content available Determination of heat transfer coefficient in the phase-change heat storage device
51%
Pavlenko A. M. , Koshlak H. V. , Piotrowski J. Z.
Structure and Environment
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2016
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tom Vol. 8, no. 4
278--281
EN
This article describes information about the research of the heat transfer coefficient from air to water on the basis of comparison of theoretical calculations with the use of mathematical modeling and experimental studies of small copies of the heat accumulator to operate in the charging mode and discharging process without phase change.
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