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Wyniki wyszukiwania dla: HYDRATION HEAT
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The Use of Liquid Crystal Thermography an Image Processing in Heat and Fluid-Flow Research
PublikacjaLiquid crystal thermography (LCT) have been used in many technical, industrial and biomedical applications [1]. During over 20 years it has been successfully applied in Department of Energy and Industrial Apparatus at Gdansk University of Technology for visualization of steady-state and transient temperature fields. In order to demonstrate feasibility of LCT techniques in practical heat transfer contexts, the authors have performed...
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Flow visualization and heat transfer investigations on the flat plate with streamwise pressure gradient
PublikacjaPaper presents experimental investigations results for film cooling on a flat plate. The main objective of the design is the streamwise pressure distribution on the flat plate as in the blade cascade. The transient and steady-state technique with liquid crystals for the surface temperature distribution with film cooling has been used in experiments in a low speed wind tunnel.
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Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources
PublikacjaA tendency to increase the importance of so called dispersed generation, based on the local energy sources and the working systems uti- lizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for...
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Numerical solution analysis of fractional point kinetics and heat exchange in nuclear reactor
PublikacjaThe paper presents the neutron point kinetics and heat exchange models for the nuclear reactor. The models consist of a nonlinear system of fractional ordinary differential and algebraic equations. Two numerical algorithms are used to solve them. The first algorithm is application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. The second involves building an analog scheme in the FOMCON Toolbox...
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Assembly of Lipopolysaccharide in Escherichia coli Requires the Essential LapB Heat Shock Protein
PublikacjaHere, we describe two new heat shock proteins involved in the assembly of LPS in Escherichia coli, LapA and LapB (lipopolysaccharide assembly protein A and B). lapB mutants were identified based on an increased envelope stress response. Envelope stress responsive pathways control key steps in LPS biogenesis and respond to defects in the LPS assembly. Accordingly, the LPS content in ΔlapB or Δ(lapA lapB) mutants was elevated, with...
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Prediction of flow boiling heat transfer data for R134a, R600a and R290 in minichannels
PublikacjaIn the paper presented is the analysis of the results of calculations using a model to predict flow boiling of refrigerants such as R134a, R600a and R290. The latter two fluids were not used in development of model semiempirical correction. For that reason the model was verified with present experimental data. The experimental research was conducted for a full range of quality variation and a relatively wide range of mass velocity....
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Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources
PublikacjaA tendency to increase the importance of so called dispersed generation, based on the local energy sources and the working systems utilizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for cogenerative...
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A simplified energy dissipation based model of heat transfer for subcooled flow boiling
PublikacjaIn the paper a model is presented based on energetic considerations for subcooled flow boiling heat transfer. The model is the extension of authors own model developed earlier for saturated flow boiling and condensation. In the former version of the model we used the heat transfer coefficient for the liquid single-phase as a reference level, due to the lack of the appropriate model for heat transfer coefficient for the subcooled...
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Effect of the inclination angle of the condenser on the heat transfer coefficient value – experimental study
PublikacjaWhen considering problem of the condensation of the refrigerant in a flow inside channel, one needs to pay attention to the shape of its cross-section, the hydraulic diameter, the channel length as well as the orientation of the channel axis in space (horizontal, vertical, inclined). This paper presents an experimental study concerning the effect of the inclination angle of the condenser with a single coil pipe on the heat transfer...
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A simple approach to heat exchanger sizing optimisation by means of entrophy generation minimisation
PublikacjaIn the paper an attempt is presented to find the method of optimization of microtube diameter with respect to optimal thermal-hydraulic conditions in the single-phase shell-and-tube heat exchangers. The approach is based on consideration of pumping power at the condition of maximum heat transfer by the heat exchanger tube system. In the optimization method the tube diameter is first specified and then appropriate calculations are...
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Heat transfer enhancement, flow visualization and friction characteristics in rib-roughened channels
PublikacjaW pracy przedstawiono wyniki badań eksperymentalnych związanych z intensyfikacją wymiany ciepła w kanałach wyposażonych w żebra, które poprawiają warunki przejmowania ciepła od ścianki do przepływającego medium. W badaniach wykorzystano system PIV oraz termografię ciekłokrystaliczną.
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Working fluid selection for Organic Rankine Cycle applied to heat recovery systems
PublikacjaPrzedstawiono algorytm obliczeń sprawności systemu ORC na bazie dużej liczby cieczy organicznych.
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The new concept of capillary forces driven evaporator with application to waste heat recovery
PublikacjaW pracy omówiono koncepcję zastosowania rurki ciepła w nowoczesnej konstrukcji parownika wspomagającego za pomocą sił kapilarnych pompę obiegu termodynamicznego czynnika. Rozwiązanie takie może znaleźć zastosowanie w domowej mikrosiłowni CHP
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Selected problems of determining an efficient operation standard in contemporary heat-and-flow diagnostics
PublikacjaW referacie wymieniono przyczyny powodujące niejednoznaczności i trudności wyznaczania wzorca sprawnej pracy turbinowych siłowni lądowych i morskich. Przeanalizowano dwie z tych przyczyn: obniżenie wartości parametrów dolotowych czynników roboczych oraz zmiany w konfiguracji połączeń pomiędzy urządzeniami składowymi obiegów cieplnych. Jako remedium na wynikające stąd trudności zaproponowano model obliczeniowy obiegu cieplnego o...
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Experimental study of flow pattern and heat transfer during steam drying of wood
PublikacjaBadania wysokotemperaturowego suszenia drewna zostały zainspirowane koniecznością instensyfikacji wymiany ciepła i masy na potrzeby przemysłu drzewnego, a w szczególności meblarskiego, w zakresie doskonalenia metod suszenia drewna, modelowania intensyfikacji wymiany ciepła i masy w elementach suszonych, opracowania ekologicznych i energooszczędnych systemów suszarniczych, ochrony środowiska związanej z racjonalnym zużyciem energii,...
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Internal heat recuperation in vapor compression and hybrid desiccant air conditioning systems
PublikacjaPraca przedstawia badania prowadzone w Katedrze Techniki Cieplnej Politechniki Gdańskiej nad wewnętrznym odzyskiem ciepła w parowo-spreżarkowych oraz adsorpcyjnych hybrydowych urządzeniach klimatyzacyjnych. Zaprezentowano wyniki analizy psychrometrycznej procesów realizowanych w urządzeniach, stanowiska badawcze urządzeń oraz uzyskane wyniki eksperymentalne.
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Application of Organic Rankine Cycle as bottoming cycle to conventional heat and power plant
PublikacjaW pracy rozważono możliwość zastosowania układu ORC w skojarzeniu z ciepłownią lub elektrociepłownią celem podniesienia stopnia wykorzystania jednostki CHP podczas eksploatacji w skali roku. Połączenie układu ORC z zawodową jednostką CHP może wpłynąć na wzrost rocznej produkcji energii elektrycznej i jednoczsne zmniejszenie fluktuacji podczas pracy bloku energetycznego. Z jednej strony następuje konwersja energii cieplnej na elektryczną...
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Experimental investigations of commercial gas boiler as a heat source for the domestic micro-CHP
PublikacjaW pracy przedstawiono wyniki badań przeprowadzonych na prototypowym stanowisku mikrosiłowni domowej ORC z kotłem gazowym jako źródłem ciepła. Wykazano, iż jest możliwa adaptacja komercyjnego kotła gazowego dla potrzeb kogeneracji w skali mikro.
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Experimental Investigation of Free Convection Heat Transfer from Horizontal Cylinder to Nanofluids
PublikacjaThe results of free convection heat transfer investigation from a horizontal, uniformly heated tube immersed in a nanofluid are presented. Experiments were performed with five base fluids, i.e., ethylene glycol (EG), distilled water (W) and the mixtures of EG and water with the ratios of 60/40, 50/50, 40/60 by volume, so the Rayleigh (Ra) number range was 3 104 Ra 1.3 106 and the Prandtl (Pr) number varied from 4.4 to 176....
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Numerical simulation of temperature distribution of heat flow on reservoir tanks connected in a series
PublikacjaThe flow of temperature distribution through a medium in thermodynamic studies plays an important role in understanding physical phenomena in chemical science and petroleum engineering, while temperature distribution indicates the degree of reaction that must be undergone to obtain the final product. Therefore, this paper aims to present and apply the exponential matrix algorithm (EMA), differential transformation algorithm (DTA),...
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Impact of Temperature and Nanoparticle Concentration on Turbulent Forced Convective Heat Transfer of Nanofluids
PublikacjaTheoretical analysis of the influence of nanoparticles and temperature on the average Nusselt (Nu) number and the average heat transfer coefficient (HTC) during the turbulent flow of nanofluid in a horizontal, round tube was carried out. The Nu number is a function of the Reynolds (Re) number and the Prandtl (Pr) number, which in turn are functions of the thermophysical properties of the liquid and the flow conditions. On the other...
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Heat Transfer of the Multicolor-Laser-Sources-Irradiated Nanoparticles in Reference to Thermal Processes
PublikacjaUnlike the standard materials, metallic nanoparticles offer enhancing the heat convertion rate which implies the maximum and average temperature boost significantly in the considered system. The work’s purpose is to examine heat transfer in the metallic nanoparticles which have been deposited on a glassy substrate, enabling the nanostructures thermoablation. Furthermore, the functionalized substrate is irradiated with multicolor-laser-sources,...
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Numerical analysis of high temperature minichannel heat exchanger for recuperative microturbine system
PublikacjaConsidering the development of energy sector, distributed small-scale power generation, e.g., gas micro-CHP, is attracting considerable interest. In such installations, the heat exchanger is one of the key components possessing a significant influence on overall performance. Most studies concentrate on units operating below 900C, which do not fulfil the requirements of gas micro-CHP. Therefore, there remains a challenge to design...
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The Laboratory Stand for the Evaluation of Heat Dissipation from the Power Cable in a Casing Pipe
PublikacjaThe current carrying capacity of a power cable determines its efficiency, which depends on its capability to dissipate heat produced inside the cable, as a result of current flow, into the surrounding. The studies were conducted to determine how the characteristics of the medium around the cable affected its temperature and, as a result, its ability to transport electricity. The experimentation in the lab and real measurements...
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Current Trends in Wick Structure Construction in Loop Heat Pipes Applications: A Review
PublikacjaThermal control systems have been introduced as an important part of electronic devices, enabling thermal management of their electronic components. Loop heat pipe (LHP) is a passive two-phase heat transfer device with significant potential for numerous applications, such as aerospace applications, high-power LEDs, and solar central receivers. Its advantages are high heat transfer capability, low thermal resistance, long-distance...
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Experiment-Based Study of Heat Dissipation from the Power Cable in a Casing Pipe
PublikacjaThe paper deals with the important challenges in terms of electricity transmission by means of underground cable lines. The power cable’s performance is characterized by an ampacity that represents its maximum electric current-carrying capacity. The ampacity of power cables depends on their ability to diffuse the heat generated by the current flow into the environment. In the performed research, the analysis of the efficiency of...
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Experimental Investigation of an Intensified Heat Transfer Adsorption Bed (IHTAB) Reactor Prototype
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An adaptive neuro-fuzzy model of a re-heat two-stage adsorption chiller
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Analysis of energy and economic efficiency water heating by heat pump air-water
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Numerical analysis of permeability and Darcy effect in heat transfer of pyramid-shaped structure
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A System for Heart Sounds Classification
PublikacjaThe future of quick and efficient disease diagnosis lays in the development of reliable non-invasive methods. As for the cardiac diseases – one of the major causes of death around the globe – a concept of an electronic stethoscope equipped with an automatic heart tone identification system appears to be the best solution. Thanks to the advancement in technology, the quality of phonocardiography signals is no longer an issue. However,...
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An innovative light child seat
PublikacjaPrzedstawiono rozwój konstrukcji i badania symulacyjne fotelika samochodowego do przewozu dziecka.
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Entropy Measures of heart rate variability for short ECG datasets in patients with congestive heart failure
PublikacjaWe investigated the usefulness of entropy measures calculated for short ECG series in distinguishing healthy subjects from patients with congestive heart failure (CHF). Four entropy measures were tested: Approximate Entropy (ApEn), Sample Entropy (SampEn), Fuzzy Entropy (Fuzzy En) and Permutation Entropy (PE), each computed for ECG series of 1000, 500, 250 and 100 RR intervals. We found that with a reduction of the data set length...
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Entropy measures of heart rate variability for short ECG datasets in patients with congestive heart failure
PublikacjaWe investigated the usefulness of entropy measures calculated for short ECG series in distinguishing healthy subjects from patients with congestive heart failure (CHF). Four entropy measures were tested: Approximate Entropy (ApEn), Sample Entropy (SampEn), Fuzzy Entropy (FuzzyEn) and Permutation Entropy (PE), each computed for ECG series of 1000, 500, 250 and 100 RR intervals. We found that with a reduction of the data set length...
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The idea of the heat storage in heat accumulator for car engine preheating before start = Koncepcja wykorzystania ciepła zakumulowanego w cieczy chłodzącej do wstępnego podgrzania silnika samochodu przed kolejnym rozruchem
PublikacjaSposób eksploatacji samochodów osobowych w miastach charakteryzuje się krótkimi przejazdami, a w przypadku pojazdów kurierów i pojazdów dostawczych również krótkimi postojami z zatrzymaniem silnika. Nowoczesne układy chłodzenia z pompą cieczy chłodzącej z napędem niezależnym od silnika stwarzają możliwość schładzania lub podgrzewania silnika zatrzymanego. Wpływ stanu cieplnego podczas rozruchu na parametry eksploatacyjne był rozważany...
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Importance of Specific Heat Characterization when Reporting New Superconductors: An Example of Superconductivity in LiGa2Rh
PublikacjaWe show that the full-Heusler compound LiGa2Rh is a superconductor with Tc = 2.4 K. The new superconductor was found as a result of an intuition-based extension of a database search for superconductors that looked for the presence of peaks in the electronic band structure near the Fermi energy. The measurement of the entropy loss during the transition from the nonsuperconducting to the superconducting state, a straightforward measurement...
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Particulate Matter Production of Small Heat Source Depending on the Bark Content in Wood Pellets
PublikacjaWood pellets as biofuel are more and more used in small heat sources in Europe. Standard wood pellets are produced from wood sawdust without bark. The paper deals about the impact of bark in wood pellets on their properties and combustion process. Special attention in this work is paid to production of particulate matter during combustion of wood pellets depending on bark content. There were experimentally produced spruce wood...
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A semi-empirical model for flow boiling heat transfer with account of the reduced pressure effect
PublikacjaIn the present study the attention was focused on the influence of reduced pressure on the predictions of heat transfer during flow boiling at the extensive range of pressures. The results of calculations were to test the sensitivity of the in-house flow boiling model with respect to the selection of the appropriate two-phase flow multiplier, which is one of the distinctive elements of that model. For this purpose a few two-phase...
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Experimental study and comparison with predictive methods for flow boiling heat transfer coefficient of HFE7000
PublikacjaThis article describes an experimental study of flow boiling of HFE7000 inside a smooth vertical channel. The investigation has been carried out in a circular stainless-steel tube with an inner diameter of 2.3 mm. The data have been collected for the applied heat fluxes q ranging from 61 to 205 kW/m2, the mass flux G ranging from 214 to 1006 kg/(m2 s), the saturation temperature Tsat ranging from 30 to 54 °C and the full range...
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Inverse heat transfer problem solution of sounding rocket using moving window optimization
PublikacjaAn Inverse Heat Transfer Problem is solved for a sounding rocket module given its geometry and measured temperature profile. The solution is obtained via moving window optimization, a technique for solving inverse dynamics. An analysis is performed to modify the method to avoid oscillatory behavior of the resulting heat flux profile. The method parameters are tuned in relation to characteristic phases of the flight. Results are...
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Prediction of flow boiling heat transfer coefficient for carbon dioxide in minichannels and conventional channels
PublikacjaIn the paper presented are the results of calculations using authors own model to predict heat transfer coefficient during flow boiling of carbon dioxide. The experimental data from various resea rches were collected. Calculations were conducted for a full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in-house model. The results show the importance of taking into...
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Impact of the inclination angle of the condenser with refrigerant R410A on heat transfer coefficient – experimental study
PublikacjaIn the paper the authors present results of a laboratory test of the condenser with refrigerant R410A. The effect of the inclination of this condenser on the heat transfer coefficient value has been considered. The test has proved that there is an optimal inclination angle of the condenser which gives maximal value of this coefficient.
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Review of Small Gas Turbine Engines and Their Adaptation for Automotive Waste Heat Recovery Systems
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AUGMENTATION OF THE CRITICAL HEAT FLUX IN WATER-Al2O3, WATER-TiO2 AND WATER-Cu NANOFLUIDS
PublikacjaThe main aim of the proposed study is therefore recognition of the phenomena accompanying nucleate boiling crisis of selected nanofluids during boiling on horizontal tubes of various outside diameters. Of particular interest is impact of contact angle and tube diameter on the value of critical heat flux. The results obtained should give more light on the nature of nucleate boiling crisis and will serve as a basis for future theoretical...
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COMPARISON OF HEAT TRANSFER CHARACTERISTICS IN SURFACE COOLING WITH BOILING MICROJETS OF WATER, ETHANOL AND HFE7100
PublikacjaThe basis of microjet technology is to produce laminar jets which when impinging the surface have a very high kinetic energy at the stagnation point. Boundary layer is not formed in those conditions, while the area of film cooling has a very high turbulence resulting from a very high heat transfer coefficient. Applied technology of jet production can result with the size of jets ranging from 20 to 500μm in breadth and 20 to 100μm...
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Implementation of the Boundary Element Method to Two-Dimensional Heat Transfer with Thermal Bridge Effects
PublikacjaThe work presents an application of the boundary element method applied to a two-dimensional conductive heat transfer. The algorithm of the method is explained and its advantages are outlined. Green's function as a fundamental solution for Poisson's equation in two dimensions was used and the direct approach was applied. The presented results concern building construction elements as typical cases of thermal bridges. Some properties...
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Proposal of a mobile medical waste incinerator with automatic waste feeder and heat recovery system
PublikacjaThe paper presents and discusses the issue of medical waste (including hazardous ones) and their proper management. Inappropriate handling of infectious medical waste directly endangers the human being health and the environment. Infectious waste must therefore be properly disposed of – one of the most commonly used methods is the thermal treatment in the incinerators tailored for this purpose. During designing an incinerator unit,...
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Heat recovery from the hybrid photovoltaic tile – experimental studies with the solar light simulator
PublikacjaConsidering the current development of micro-cogeneration energy sources, supported by the national prosumer policy and the act on the renewable energy sources, there is a great demand for the effective solar technologies. In this area, the photovoltaic cells with a combined conversion of the solar radiation energy into the electrical and thermal energy (PV/T cells) seem to be attractive. They are already widely available and treated...
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A simplified energy dissipation based model of heat transfer for post-dryout flow boiling
Publikacjamodel for post dryout mist flow heat transfer is presented based on considerations of energy dissipation in the flow. The model is an extension of authors own model developed earlier for saturated and subcooled flow boiling. In the former version of the model the heat transfer coefficient for the liquid singlephase convection as a reference was used, due to the lack of the appropriate model for heat transfer coefficient for the...
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Free convective heat transfer structures as a function of the width of isothermal horizontal rectangular plates
PublikacjaZaprezentowano rezultaty badań eksperymentalnych konwekcyjnej wymiany ciepła od izotermicznych płyt prostokątnych skierowanych ku górze. Na podstawie przeprowadzonych wizualizacji zaproponowano dwa modele struktur przepływu. Rozwiązania analityczne dla tych modeli przedstawiono w postaci zależności liczb Nusselta Rayleigh'a. Stwierdzono, że przepływ koncentryczny występuje dla małych wartości liczb Ra, szczególnie w przypadku płyt...