Investigation of heat transfer processes in combined systems of evaporation-condensation type and optimization of system performance

Formulation and implementation of this work is stipulated by the necessity of new, more efficient heat transfer means of evaporation-condensation type (ICT) in comparison with the ordinary ICT devices and systems, which improvement has reached the limit of their potential. Such heat transfer means, in particular, can be multi-element ICT systems with both structurally identical and non-identical components; systems with common steam and condensate and branched parts of the heat supply and/or heat sink; bimetallic systems with different combinations of body materials and capillary structure. Such systems are combined according to constructive characteristics and by the indicator of combination of different materials in a single unit.

On the basis of conducted studies of heat transfer process regularities and complex thermalphysic studies of heat transfer characteristics of combined heat transfer ICT systems, developed scientifically grounded methods of rational designing and patented new specific scientific and technical decisions concerning these systems it is proved that the combined evaporation-condensation heat transfer systems (ICS) by complex of inherent thermal, technological and operational advantages, benefits, characteristics meet the requirements and conditions that are put forward to the passive heat sink systems and thermal control system to improve the efficiency, reliability and safety of running the facilities of power engineering and industry, to ensure optimal thermal operating conditions of different types of equipment, devices, instruments.

Scientifically grounded methods of providing the effective and reliable running of the combined systems of heat evaporation-condensation type are worked out. Based on the study of structural, hydrodynamic and capillary transport properties of fine-fibre capillary structures for combined ICS, relations of the pores size, permeability and capillary pressure of the initial structural parameters, regularity of capillary filtering are obtained. Regularities for determining the limits of heat transfer capability of ICT systems under the influence of various thermal factors are got. Relations for determination of heat transfer and thermal resistance processes characteristics, recommendations for intensification of heat exchange processes are obtained. Actions to improve the heat transfer capability of ICT systems are grounded. Relations to determine the optimal parameters of metal-fibrous capillary structures and dependencies to determine the optimal constructive parameters of ICS in terms of maximum efficiency of heat transfer processes are got. On the basis of the revealed regularities, obtained dependencies and relationships developed methods of thermal calculation are developed. Analytical relations are established for comparing the capacity of ICT heat transfer system and traditional heat transport systems.

Specific technological solutions to provide effectiveness and reliability of the combined heat transfer ICT systems running is worked out. The original scheme-constructional solutions for combined ICS are designed to improve the efficiency, reliability and operation safety of energy facilities and industry, to ensure optimal thermal conditions of the various types of equipment, devices, instruments, that are protected by patents of Ukraine.

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