The influence of radiation-conductive heat exchange on thermal regimes of oxide crystal growth from the melt. - The manuscript.
The candidate of engineering science degree thesis by specialty 05.14.06 - Technical thermal physics and industrial power engineering. - National Technical University of Ukraine "Kiev polytechnic institute", Ministry of education and science of Ukraine, Kyiv, 2006.
Thesis is devoted to development of mathematical modeling of complex radiation-conductive heat exchange during oxide crystals growth from the melts. A special emphasis is devoted to numerical calculation of radiation in emissive absorbent cylindrical crystals with semitransparent and opaque, with fixed and moving curvilinear surfaces.
Modification scheme of discontinuous coefficients smoothing that takes into account radiation component in energy balance on interface is offered to solve Stefan problem in conditions of radiation-conductive heat exchange.
In the work influence of radiation component on temperature fields of crystal-melt system and temperature conditions of interface is analysed. It is concluded radiation heat exchange is basic mechanism of heat extraction from the interface. Possibility of radiation screening is viewed.
On basis of thermal Stefan problems numerical models of crystal growth processes with kinetic process and facet formation on interface are developed.
To obtain kinetic coefficient of crystal growth process experimental-numerical method was developed and proved.
To take into account radiation-conductive heat exchange in global modeling of semitransparent crystal growth processes variants are proposed.
Keywords: radiation-conductive heat exchange, temperature conditions of interface, oxide crystals, supercooling on interface.
Thermodynamic properties and characteristics of highly dispersed liophobic systems as a new heterogeneous working media. - The manuscript.
The candidate of engineering science degree thesis by specialty 05.14.06 -Technical thermal physics and industrial power engineering. - National Technical University of Ukraine "Kiev polytechnic institute", Ministry of education and science of Ukraine, Kyiv, 2008.
The work is devoted to the providing of the thermodynamic and thermophysical basis of a new heterogeneous working media (HWM) synthesis for different types of energy devices based on highly dispersed liophobic systems (HDLS). It deals with the method preparation of HDLS thermophysical properties during the isothermal compression-expansion when the system can accumulate energy due to interphase expansion.
The HDLS "liquid - porous liophobic solid (PLS)" thermodynamic model on the base of capillary, globular and spongy models of PLS is suggested for HDLS investigation. It contains the mechanism of hysteresis phenomenon in HDLS isothermal compression-expansion process and enables to devise a method of HDLS general thermophysic properties determination: pressure of intrusion and extrusion; volume of intrusion; work and heat of intrusion and extrusion; interphase intrinsic energy change; wetting, topological and adhesive hysteresis components; isothermal compression coefficient; thermal pressure coefficient.
The HDLS compression-expansion process experimental investigation giving the quantitative description of the HDLS thermophysic properties and hysteresis in processes considered is realized and the analytical methods suggested are tested.
The thermodynamic and thermophysical basis of HWM synthesis for different types of energy devices is provided. The next HWM energy devices are designed, produced and tested: automobile shock absorber (hydrocapillary damper), automobile bumper (on the base of hydrocapillary dampers) and actuator (on the base of hydrocapillary accumulator).
Keywords: highly dispersed liophobic system, heterogeneous working media, interphase/interface, thermophysical properties.
Global heat exchange modelling and control at semitransparent materials crystal growth installations. – The manuscript.
The thesis for competition of scientific degree of Candidate in technical sciences according to on speciality 05.14.06 – Technical thermal physics and industrial heat and power engineering. – National Technical University of Ukraine «Kyiv Polytechnic Institute», Ministry of education and science of Ukraine, Kyiv, 2009.
The thesis is devoted to development of numerical models of radiation-convective heat exchange at crystal growth from melts of semitransparent materials for the different types of scintillation crystals and growth methods. The thesis is also devoted to research of temperature conditions control methods at directed crystallization processes.
The generalized mathematical statement of 2D axisymmetric problem of radiation-convective heat exchange at crystallization installations is developed considering selectivity of semitransparent materials optical properties. Numerical calculations are conducted and crystallization processes are studied in the crystal-melt system for materials with properties of oxide and alkaline-haloid crystals with taking into account selectivity of their absorptance and usage of dynamically rebuilt mesh. The simplified versions of global heat exchange models are analysed for their application at real-time control of directed crystallization realizing AHP and Bridjman methods. The global numerical model of radiation-convective heat exchange is developed for the Kiropulos method; the influence of carbonate impurities on thermal conditions of caesium iodide crystal growth is investigated. The influence of optical properties selectivity is conducted. It is confirmed that impurity introduction with the purpose of absorption change is an effective technique for crystallization process control. It is shown that adjustment of radiation heatsink from the melt with the screen is an effective and fast-response method of thermal regimes control at crystal growth.
Keywords: radiation-convective heat exchange, temperature conditions at crystallization interface, scintillation materials, numerical models of crystallizers.
Designing, modeling and optimization of the elements of solar hot water supply systems. - The manuscript.
The dissertation for a Candidate of Engineering Sciences degree, speciality 05.14.06 — Technical thermo-physics and engineering heat energetic. -National technical university of Ukraine NTUU "KPI", Kiev, 2011.
The thesis is devoted to investigation of thermo-physical efficiency of solar hot water supply systems, designing on this base the new engineering solutions for effective construction of the heliosystem elements, methods of their tests and thermal calculation with use of mathematical modeling and conditions parameters optimization. The designed in the thesis new engineering solutions, thermal calculations methods for solar collectors of running and accumulative types and other elements (heat exchangers and thermal receiver) allow providing the design and calculation of the effective constructions of the elements of hot water supply heliosystems with solar collectors equipped by such attributes of quality as anticonvection structure, screen heat insulation and selective coating. The proposed in the work new methods for heat tests of solar collectors of running and accumulative types and heat exchangers — recuperators and based on them procedure for determination of their construction parameters allow to define sufficiently reasonably and exactly the experimental estimations of these parameters, that is constants of their mathematical models, and may be use at the certification tests of helioequipment.
Keywords: solar collector, heat exchanger, thermal receiver, solar hot water supply system, mathematical modeling, exergic analysis, optimization, anticonvection structure, screen heat insulation.
Influence of temperature and weather and operational factors on the efficiency of heat supply. – The manuscript.
Dissertation for candidate degree of technical sciences on speciality 05.14.01 – Power system and complex. – National Technical University of Ukraine «Kyiv Polytechnic Institute», 2011.
The thesis is devoted to the development of methodological aspects, methods and models the effect of temperature and weather factors in the design, operation and modernization of heating systems, development of the impact of operational factors on the efficiency of heating elements to increase the efficiency of heat consumption. Developed mechanisms for analysis, evaluation and monitoring of performance indicators of heating on the basis of analyzing the performance of the heat supply enterprises, the actual temperature of outdoor air for the last fifteen years, developed recommendations for consideration of temperature and weather and operational factors during the feasibility of heat sources, thermo projects and buildings in the implementation of energy audit. A mathematical model of the thermal state of the premises, which allows us to provide quantitative estimates of compliance comfortable temperature conditions in buildings with varying degrees of thermal protection and to analyze ways to reduce heat loss. A method for evaluating the effectiveness of implementing energy efficiency measures in buildings subject to weather conditions.
Keywords: heating system, temperature and weather conditions, the thermal state of the building, projects on energy saving, efficiency of the heat utilization.