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Search results for: heat transfer intensification
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Heat transfer intensification by enlarged surface roughness in the plate heat exchanger
PublicationIn the paper an experimental analysis of passive heat transfer intensification technique employed in the case of the plate heat exchanger is presented. The passive intensification was obtained by a modification of the heat transfer surface. The roughness of surface was increased by a use of glass micro-beads. Single-phase convective heat transfer in the water-water system was studied. The experiment was accomplished in two stages....
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Experimental study of heat transfer intensification in surface cooling using microjets
PublicationW pracy przedstawiono badania eksperymentalne intensyfikacji wymiany ciepła podczas chłodzenia powierzchni mikrostrugami. Wyniki badań porównano z własnym modelem teoretycznym zjawiska.
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Heat transfer intensification by jet impingement – numerical analysis using RANS approach
PublicationJet impingement is a method of the heat transfer enhancement applied in the engineering systems. The idea is to generate fast-flow fluid jet which impinge on the heated (or cooled) surface, causing significantly higher heat transfer rate. Although some flat surface jet impingement cases are described in the literature, the validated data is still limited. The reason is coming from the fact, that these flows are hydrodynamically...
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Intensyfikacja wymiany ciepła przy pomocy mikrostrug = Heat transfer intensification using microjets.
PublicationW pracy przedstawiono wyniki badań eksperymentalnych nad intensyfikacją strumienia ciepła przy pomocy pojedynczej mikrostrugi wody. W pracy przedstawiono wyniki badań dla dysz o średnicy 180 i 280 mikrometrów.
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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
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HEAT TRANSFER ENGINEERING
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Recent advances of selected passive heat transfer intensification methods for phase change material-based latent heat energy storage units: A review
PublicationThe following article overviews recent studies regarding heat transfer enhancement methods, explicitly focusing on fins and coils utilization, in phase change material-based latent heat thermal energy storage systems. It discusses the influence of various geometrical and material parameters on the melting and solidification processes, as well as the orientation of the heat transfer surface within the storage tank. Additionally,...
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INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
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EXPERIMENTAL HEAT TRANSFER
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HEAT AND MASS TRANSFER
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Heat Transfer-Asian Research
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Frontiers in Heat and Mass Transfer
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Interfacial Phenomena and Heat Transfer
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Microjet technology as a perspective intensification method for high performance heat exchangers
PublicationIn the paper two oryginal designs of compact heat exchangers with intensification effect produced by microjets are presented. The technology of microjets manufacturing is an "inhouse" patented design. The idea of such heat exchanger is shown together with the flow and thermal characteristics of the prototypes. The results of performer measurements are satisfactory and encourage for further research of the original designs.
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Heat Transfer
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Boiling heat transfer performance of the thermosiphon heat exchanger
PublicationPrzedstawiono wyniki badań eksperymentalnych prototypowego, termosyfonowgo wymiennika ciepła. W szczególności określono wpływ geometrii pęku rur, stanu powierzchni rurek oraz poziomu cieczy w parowniku na wydajność cieplną wymiennika.
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HEAT TRANSFER CHARACTERISTICS OF ENHANCED SHELL AND COIL HEAT EXCHANGER
PublicationIn the paper authors presented their own constructions of shell and tube heat exchangers with intensified heat transfer. The shell and coils heat exchangers are in common use in heat ventilations and air conditioning systems. Those types of recuperators are quite simple constructions, the low value of pressure drops and good conditions of heat transfer. The present study shows an experimental investigation of the heat transfer...
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Heat transfer characteristics of a two-phase thermosyphon heat exchanger
PublicationPrzedstawiono wyniki badań wpływu geometrii parownika, rodzaju rur użytych do budowy parownika, rodzaju cieczy pośredniej oraz poziomu cieczy nad najwyższym rzędem rur na działanie dwufazowego, termosyfonowego wymiennika ciepła. Zaprezentowano algorytm obliczeń przedstawionego wymiennika.
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Heat transfer of two-interacting microjets
PublicationThe present paper paid particular attention to the flow and heat transfer performance for two microjets impinging upon the heated surface by means of experimental investigations.
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Modelling of heat transfer in flow boiling
PublicationW pracy przedstawiono zagadnienia związane z modelowaniem wrzenia w przepływie w kanałach o małej średnicy. Przedstawiono modyfikację rozwijanej przez autorów korelacji umożliwiającej wyznaczanie współczynnika przejmowania ciepła podczas wrzenia w przepływie.
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Simplified modelling of heat transfer in groundwater
PublicationPrzenoszenie ciepła w wodach podziemnych jest skomplikowanym, przestrzennym procesem. Z tego względu do rozwiązywania zadań praktycznych celowe jest konstruowanie modeli uproszczonych. W pracy zaproponowano sposób formułowania modelu dwuwymiarowego. Został on pozytywnie zweryfikowany na przykładzie badania przyczyn strat energii cieplnej w elektrowni Kozienice.
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WSEAS Transactions on Heat And Mass Transfer
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American Journal of Heat and Mass Transfer
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JP Journal of Heat and Mass Transfer
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Journal of Heat and Mass Transfer Research
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ASME Journal of Heat and Mass Transfer
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High Performance Tubular Heat Exchanger with Minijet Heat Transfer Enhancement
PublicationIn the paper, the original cylindrical heat exchanger with minijets (MJHE) was introduced. The systematic experimental analysis of the prototype heat exchanger was described with special attention paid to such parameters as the heat transfer effectiveness, heat transfer rates, overall heat transfer coefficients, and pressure drop. The heat transfer coefficients were determined based on Wilson plot method, the most suitable approach...
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Possibilities of heat transfer augmentation in heat exchangers with minichannels for marine applications
PublicationIn the paper, new trends in development of microchannel heat exchangers are presented. The exchangers developed in this way can be applied in marine applications. Main attention was focused on heat exchangers design with reduced size of passages namely based on microchannels. In our opinion future development of high power heat exchangers will be based on networks micro heat exchangers.
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Applicability of arrays of microjets heat transfer correlations to design compact heat exchangers
PublicationThe article presents experimental studies on a compact heat exchanger with heat transfer intensification by means of impinging microjets. The pursuit to provide high performance of heat exchangers is a response to the demand both in economics and in the universal tendency to miniaturization of industrial equipment. This paper presents the design and tests of a prototype, microjet heat exchanger. The modular design of the heat exchanger...
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Thermal-FSI modeling of flow and heat transfer in a heat exchangerbased on minichanels
PublicationIn this paper selected numerical modelling problems for an advanced thermal-FSI ("Fluid Solid Interaction") mini-channel heat exchanger model are presented. Special attention is given to the heat transfer between the separated mediums for different mass flows. Similar modelling problems have also been discussed in the literature dedicated to numerical and theoretical modelling problems for typical heat exchangers [1, 2, 3]. Basic...
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Heat transfer and pressure drop characteristics of the silicone-based plate heat exchanger
PublicationThe paper presents an experimental investigation of a silicone based heat exchanger, with passive heat transfer intensification by means of surface enhancement. The main objective of this paper was to experimentally investigate the performance of a heat exchanger module with the enhanced surface. Heat transfer in the test section has been examined and described with precise measurements of thermal and flow conditions. Reported...
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Co-simulation strategy of transient CFD and heat transfer in building thermal envelope based on calibrated heat transfer coefficients
PublicationThe paper presents a strategy to develop a fully transient numerical model of a heat transfer in building, using a transient CFD model of indoor air and a thermal envelope model, running in a co-simulation. The strategy relies on the utilization of RANS with a high-Re turbulence model and a wall function, which enables to use a coarse computational mesh limiting the computational time. Since wall functions give invalid heat transfer...
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Natural convective heat transfer from isothermalconic
PublicationTheoretical considerations on convective heat transfer from isothermal upward conicalsurfaces have been presented. The physical model of this phenomenon consists of an isothermalcone of inclination angle (φ) between the cone generating line (X) and the radius (R) of the cone base. The angle is a parameter of conical surface which varied from (φ = 0−circular horizontal plate) to (φ = π/2—vertical cylinder) . Onthe basis of Navier–Stokes...
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Modelling of heat transfer in supercritical pressure recuperators
PublicationIn the paper presented is analysis of convective flow heat transfer at supercritical pressure in channels of heat exchanger working in the thermodynamic cycle. The modelling is based on the division of the flow into three regions, namely the heavy fluid, a two phase flow consisting of the heavy and light fluids and finally the light fluid flow. Modelling is concentrated on the region of simultaneous flow of two fluids divided into...
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Heat transfer phenomena of glassy carbon foams
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A study of flow boiling heat transfer in minichannels
PublicationW pracy przedstawiono badania eksperymentalne wrzenia w przepływie w minikanale o średnicy wewnętrznej 2.3mm i długości 38cm. Uzyskano rozłady temperatury wzdłuż ścianki kanału oraz lokalne współczynniki przejmowania ciepła. Dane skorelowano z korelacją półempiryczną uzyskując zadowalającą zgodność.
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The impact of nozzle configuration on the heat transfer coefficient
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Modelling of convective heat transfer in flow boiling.
PublicationW pracy przedstawiono rozważania dotyczące modelowania przepływu z wrzeniem w zastosowaniu do kanałów o małej średnicy. Stwierdzono,że stosowanie korelacji obowiązujących dla średnic konwencjonalnych nie sprawdza się z praktyką w przypadku małych średnic.
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Heat transfer augmentation using liquid crystal
PublicationPraca przedstawia zastosowanie techniki wizualizacji ciekłokrystalicznej dobadań wymiany ciepła na płaskiej powierzchni z zaburzaczami. Folia ciekło-krystaliczna została umieszczona na powierzchni, aby określić przebieg izoterm. Obraz rejestrowano kamerą JVC, a następnie analizowano komputerowo. Procedura eksperymentalna pozwala na otrzymanie pełnej informacji dotyczącej wymiany ciepła (na powierzchni płaskiej z elementami ustawionymi...
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The influence of microjet array area ratio on heat transfer in the compact heat exchanger
PublicationThe paper describes the comprehensive study on the effect of microjet array geometrical parameters on the heat transfer enhancement in the modular heat exchanger. The conducted experimental study provides an experimental database on single phase submerged microjet heat transfer. The Wilson plot method was applied to determine the heat transfer coefficients in the laminar and transition flow regimes of a liquid-to-liquid heat exchanger....
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Turbulent heat transfer in thin liquid films at low and high heat fluxes
PublicationW pracy przedstawiono rozważania turbulentnej wymiany ciepła w cienkich filmach cieczowych powstałych w wyniku uderzenia strugi przy małych i dużych strumieniach ciepła. W ostatnim przypadku może dojść do wrzenia filmu cieczowego. Oba zjawiska zamodelowano i uzyskano odpowiednie rozkłady temperatury i pedkosci.
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Flow distribution and heat transfer in minigap and minichannel heat exchangers during flow boiling
PublicationThe topic of boiling heat transfer in miniscale geometries has focused the ever increasing interest of researchers in recent years. However, most of the works are related to mini- and microchannels and much less to minigaps. Meanwhile, minigaps allow for more comprehensive experimental studies, i.e. flow visualisations due to the flat, two-dimensional configuration of the flow. The results of the experimental investigations of...
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Heat transfer in plate heat exchanger channels: experimental validation of selected correlation equations
PublicationThis study is focused on experimental investigation of selected type of brazed plate heat exchanger. The Wilson approach was applied in order to estimate heat transfer coefficients for the PHEx passages. The main aim of the paper was to experimentally check ability of several correlations published in the literature to predict heat transfer coefficients by comparison experimentally obtained data with appropriate predictions. The...
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Heat transfer in plate heat exchanger channels: experimental validation of selected correlation equations
PublicationThis study is focused on experimental investigation of selected type of brazed plate heat exchanger. The Wilson approach was applied in order to estimate heat transfer coefficients for the PHEx passages. The main aim of the paper was to experimentally check ability of several correlations published in the literature to predict heat transfer coefficients by comparison experimentally obtained data with appropriate predictions. The...
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Natural convective heat transfer from isothermal cuboids
PublicationThe paper presents results of theoretical and experimental investigations of the convective heat transfer from isothermal cuboid. The analytical solution was performed taking into account complete boundary layer length and the manner of its propagation around isothermal cuboid. It arises at horizontal bottom surface and grows on vertical lateral surface of the block. After changing its direction, the boundary layer occurs above...
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Experimental investigations on heat transfer enhancement in shell coil heat exchanger with VARIABLE Baffles GEOMETRY
PublicationThe paper presents the possibility of using passive intensification of heat transfer in the form of baffles to increase the energy efficiency of the shell and coil heat exchanger. The experiment was carried out by using a modular coil heat exchanger in the form of an electric heater. Water was used as a working fluid with constant thermal-flow parameters at the inlet of the module. It should be noted that experiments were made...
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Hydrodynamics and heat transfer in bubbly flow in the turbulent boundarylayer
PublicationW pracy przedstawiono oryginalne podejście do modelowania przepływu pęcherzykowego w warstwie przyściennej i w kanale. Podejście oparte jest na sumowaniu energii dyssypacji pochodzącej od przepływu ścinającego w kanale oraz dyssypacji pochodzącej od obecności pęcherzyków. W wyniku otrzymuje się naprężenia styczne ekwiwalentnego przepływu jednofazowego. Zaproponowano własne podejście do modelowania stopnia zapełnienia opisane równaniem...
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Modelling of heat and mass transfer through wooden buildings
PublicationThe aim of this review paper is to examine the most recent available studies dealing with theoretical, numerical and experimental aspects related to modelling of heat and mass transfer through wooden buildings. The main thermophysical, mechanical and hygrometric properties of wood are firstly discussed. Then, the basic governing equations of heat and mass transfer phenomena are presented. A detailed description of the physical...
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Free Convection Heat Transfer from Horizontal Cylinders
PublicationThe results of experimental investigation of free convection heat transfer in a rectangular container are presented. The ability of the commonly accepted correlation equations to reproduce present experimental data was tested as well. It was assumed that the examined geometry fulfils the requirement of no-interaction between heated cylinder and bounded surfaces. In order to check this assumption recently published correlation equations...
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Heat and mass transfer in air-fed pressurised suits
PublicationOpisano konieczność modelowania transportu masy i ciepła w kombinezonach ochronnych. Omówiono różne sposoby modelowania wymiany ciepła, łącznie ze sprzężoną wymianą ciepła. Uwzględniono również ludzki metabolizm i turbulentne mechanizmy wymiany masy i ciepła. Publikacja opisuje również sposób modelowanie turbulentnych przepływów wieloskładnikowych. Pokazano również porównanie obliczeń z eksperymentem.