Wyniki wyszukiwania dla: HEAT ENERGY
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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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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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Ocean mixed layer dynamics: high-resolution simulations of wind, wave and convective effects
Dane BadawczeThis dataset contains results of high-resolution numerical simulations of the ocean mixed layer (OML) forced by wind, waves and cooling from the atmosphere, i.e., under strongly turbulent, convective conditions. The goal is to provide detailed, three-dimensional information about OML circulation, turbulent kinetic energy, and temperature and salinity...
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Photovoltaic module temperature stabilization with the use of phase change materials
PublikacjaThe worldwide growth of photovoltaics (PVs) has formed an exponential curve for more than four decades. During this period of time, PVs have evolved from a pure niche market of small-scale applications towards becoming a mainstream electricity source. The influence of temperature on the electrical parameters of crystalline silicon solar cells and solar modules is well described in the literature. In order to diminish these effects,...
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Charakterystyka eksploatacyjna pomp ciepła zainstalowanych w oczyszczalni ścieków
PublikacjaW artykule przedstawiono charakterystykę eksploatacyjną sprężarkowych pomp ciepła zainstalowanych w oczyszczalni komunalnej i wykorzystujących ścieki oczyszczone jako dolne źródło ciepła. Zastosowanie ścieków oczyszczonych jest uzasadnione ich dostępnością oraz stosunkowo wysoką temperaturą (10-25°C). Prawidłowa eksploatacja układu wymaga zastosowania pośredniego obiegu parowacza oraz regularnych zabiegów czyszczenia wymiennika...
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How to Meet the Green Deal Objectives—Is It Possible to Obtain 100% RES at the Regional Level in the EU?
PublikacjaThe subject matter discussed in the article concerns the problem of the energy transformation of the European Union (EU) countries. In the case of the EU, the energy transformation has specific characteristics due to formal legal and institutional provisions. This means that the member states are obliged to implement the adopted Community Energy Strategy, which was defined under the European Green Deal. According to the EU policy,...
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The topography of strontium–borate glasses and glass-ceramics containing bismuth and vanadium oxides measured with SEM method
Dane BadawczeThe topography of strontium–borate glasses and glass-ceramics containing bismuth and vanadium oxides was measured by SEM.
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Superconductivity in the intermetallic compound Zr5Al4
PublikacjaPolycrystalline Zr5Al4 was synthesized using the arc-melting method. Powder X-ray diffraction confirms the previously reported crystal structure of the Ti5Ga4-type P63/mcm with lattice parameters: a = 8.4312(6) A , and c = 5.7752(8) A . Electrical resistivity and low-temperature magnetic susceptibility measurements indicate that Zr5Al4 exhibits superconducting behavior below 2 K. The normalized heat capacity jump at Tc= 1.82 K...
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Thermal analysis of Magnetohydrodynamics (MHD) Casson fluid with suspended Iron (II, III) oxide-aluminum oxide-titanium dioxide ternary-hybrid nanostructures
PublikacjaThis study is carried out to enhance and analyze the thermal performance of non-Newtonian Casson fluid by immersing Ternary hybrid nanoparticles Fe3O4-Al2O3-TiO2 uniformly. To model the behaviour of such complex phenomena mathematically, a system of complex transport differential equations is developed by utilizing a non-Fourier heat transfer model for energy transport. The non-dimensional system of transport equations involving...
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Neoclassical Navier–Stokes Equations Considering the Gyftopoulos–Beretta Exposition of Thermodynamics
PublikacjaThe seminal Navier-Stokes equations were stated even before the creation of the foundations of thermodynamics and its first and second laws. There is a widespread opinion in the literature on thermodynamic cycles that the Navier-Stokes equations cannot be taken as a thermodynamically correct model of a local "working fluid", which would be able to describe the conversion of "heating" into "working" (Carnot's type cycles) and vice...
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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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Molecular mechanism and energetics of coupling between substrate binding and product release in the F 1 -ATPase catalytic cycle
PublikacjaF1-ATPase is a motor protein that couples the rotation of its rotary γ subunit with ATP synthesis or hydrolysis. Single-molecule experiments indicate that nucleotide binding and release events occur almost simultaneously during the synthesis cycle, allowing the energy gain due to spontaneous binding of ADP to one catalytic β subunit to be directly harnessed for driving the release of ATP from another rather than being dissipated...
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Neural Modelling of Steam Turbine Control Stage
PublikacjaThe paper describes possibility of steam turbine control stage neural model creation. It is of great importance because wider application of green energy causes severe conditions for control of energy generation systems operation Results of chosen steam turbine of 200 MW power measurements are applied as an example showing way of neural model creation. They serve as training and testing data of such neural model. Relatively simple...
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Non-Coaxially Rotating Motion in Casson Martial along with Temperature and Concentration Gradients via First-Order Chemical Reaction
PublikacjaThe effect of non-coaxial rotation on the transport of mass subjected to first-order chemical reaction is studied analytically. The effects of thermal radiation, buoyancy, constructive and destructive chemical reactions along with Casson fluid in rotating frame are discussed. Time evolution of primary and secondary velocities, energy and solute particles are analyzed. The behavior of flow under the variation of intensity of magnetic...
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Physical and numerical modelling of heat-flow processes in tangentially pulverized fuel-fired boiler
PublikacjaPraca przedstawia wykorzystanie eksperymentalnego modelowania fizycznego kwasowo-zasadowego do modernizacji kotła pyłowego z tangencjalną komorą spalania w aspekcie ograniczenia emisji toksycznych składników węgla, siarki i azotu oraz doboru optymalnych parametrów termodynamicznych mieszania i spalania. Dodatkowo, w celu porównania wyników pomiarów kotła po modernizacji, wykonano obliczenia numeryczne z zastosowaniem oprogramowania...
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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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Operation of the 900 MW power plant with the ORC supplied from three heat sources
PublikacjaThe chapter is aimed at utilisation of waste heat in the reference supercritical power plant in the manner to produce electricity in ORC installation. The waste heat is available in the form of a stream of hot water at 90°C, recovered from the exhaust gases in the amount of 200MW. Such low enthalpy heat source is rather insufficient to produce a good quality vapour to feed the ORC turbine. Therefore an original approach to increase...
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Stress corrosion cracking of the 26H2MF and 34HNM constructional allaysteels of different heat treatment in hydrocarbons
PublikacjaBadane są dwie stale stopowe 26HZMF i 34HNM o różnych właściwościach mechanicznych w różnych środowiskach.
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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...
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Influence of porous coating on heat transfer during flow boiling of R22, R134a and R407C
PublikacjaPrzedstawiono wpływ pwłoki porowatej w pozionej rurce podczas wrzenia w przepływie i spadku ciśnienia czynników chłodniczych R22, R134a i R407C.
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Review of Small Gas Turbine Engines and Their Adaptation for Automotive Waste Heat Recovery Systems
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Application of mechanical Barkhausen noise in assessment of X20 steel properties after heat treatment
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Thermal-hydraulic issues of flow boiling and condensation in organic Rankine cycle heat exchangers
PublikacjaW pracy przedstawiono szereg zagadnień cieplno-przepływowych podczas wrzenia i kondensacji w przepływie w wymiennikach ciepła obiegu ORC. Uwzględniono przemiany fazowe. Analizowano zagadnienia stabilności pracy wymienników oraz ich dynamikę
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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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Numerical investigation of conjugate heat transfer in the presence of two fluid separated by a rigid wall
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Heat Transfer in Adsorption Chillers with Fluidized Beds of Silica Gel, Zeolite, and Carbon Nanotubes
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Two bacterial small heat shock proteins, IbpA and IbpB, form a functional heterodimer
PublikacjaSmall heat shock proteins (sHsps) are a conserved class of ATP-independent chaperones which in stress conditions bind to unfolded protein substrates and prevent their irreversible aggregation. Substrates trapped in sHsps-containing aggregates are efficiently refolded into native structures by ATP-dependent Hsp70 and Hsp100 chaperones. Most γ-proteobacteria possess a single sHsp (IbpA), while in a subset of Enterobacterales, as...
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Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review
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EFFECT OF WORKING FLUID SELECTION ON THERMAL PERFORMANCE OF HEAT EXCHANGER FILLED BY THE POROUS MATERIAL
PublikacjaThermal management of electronics semiconductor technologies that are located i.e. in a novel marine power plants or computer server rooms become very important issue for designers of such systems. Motivation and need for research in development of novel cooling strategies for modern electronics is of paramount importance. Heat exchangers filled by the porous material are a novel research topic in current heat pipe science. The...
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Technical and economic conditions of supplying residential consumers with heat from nuclear power plant
PublikacjaThe reduction of CO2 emission requires technological shift towards carbon-free options. Cogeneration of electricity and heat based on coal and natural gas will experience generation cost increase, if the costs of emissions are imposed on the plant operators. Therefore, nuclear and renewable options should be considered. In this paper, we present the concept of electricity and heat supply system with nuclear condensing turbine adapted...
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Numerical Investigation of Nuclear Reactor Kinetic and Heat Transfer Fractional Model with Temperature Feedback
PublikacjaAbstract—In the paper, the numerical results concerning the kinetics and proposed heat exchange models in nuclear reactor based on fractional calculus are presented for typical inputs. Two fractional models are proposed and compared with the model based on ordinary derivative. The first fractional model is based on one of the generalized Cattaneo equations. The second one is based on replacing the ordinary to fractional order of...
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Prediction of flow boiling heat transfer coefficient for carbon dioxide in minichannels and conventional channels
PublikacjaIn the paper are presented the results of calculations using authors own model to predict heat transfer coefficient during flow boiling for carbon dioxide. The experimental data from various researches were scrutinised conducted for a full range of quality variation and wide range of mass velocity. The aim of the study was to test the sensitivity of the in-house model. The work shows the importance of taking into account surface...
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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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Pipeline system for heat transportation from nuclear power plant — An optimizing approach
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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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Modelling of two-component turbulent mass and heat transfer in air-fed pressurised suits
PublikacjaIn this paper the modelling of an important industrial problem is addressed, which involves the two-component turbulent flow with heat transfer that takes place inside protective clothing. The geometry of the flow boundaries is reconstructed in a CAD system from photogrammetry scan data. The overall model is sufficiently realistic to allow, after validation, design improvements to be tested. Those presented here allow the reduction...
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Nucleate pool boiling heat transfer from small horizontal smooth tube bundles
PublikacjaPrzedstawiono wyniki pomiarów współczynnika przejmowania ciepła podczas wrzenia wody destylowanej, metanolu i R141b na poziomym pęku rur gładkich, który składał się z 19 rurek, ogrzewanych elektrycznie, w układzie przestawionym i podziałce 1.7d oraz 2.0d. Wyznaczono również wartości współczynnika wpływu pęku. Podano równanie korelacyjne do obliczania średniego współczynnika przejmowania ciepła
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Natural convective heat transfer from isothermal horizontal, vertical and inclined plates - a review
PublikacjaW artykule przedstawiono przegląd otrzymanych przez różnych badaczy korelacji eksperymentalych, teoretycznych i numerycznych, opisujących wymianę ciepła od izotermicznych płyt o różnym kącie pochylenia. Przedstawiono model matematyczny zjawiska. Opisano stosowane metody badawcze i wskazano przyczyny rozbieżności pomiędzy przedstawionymi przez wielu autorów wynikami.
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The use of liquid crystal thermography and particle image velocimetry in the exploration of heat transfer measurements
PublikacjaArtykuł dotyczy badań eksperymentalnych wymiany ciepła w modelowym wymienniku ciepła z turbulizatorami przepływu przy użyciu termografii ciekłokrystalicznej i cyfrowej anemometrii obrazowej.
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Intensyfikacja wymiany ciepła przy pomocy mikrostrug = Heat transfer intensification using microjets.
PublikacjaW 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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Numerical modeling of cross-flow heat exchanger for air-conditioning purposes in preliminary study.
PublikacjaPraca przedstawia wyniki obliczeń numerycznych krzyżowego płytowo-rurowego wymiennika ciepła przeznaczonego do celów klimatyzacyjnych w początkowym etapie jego projektowania.
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Analysis of possibility and purposefulness of application of waste-heat boilers to trailing suction hopper dredgers
PublikacjaThis paper presents an analysis of possibility and purposefulness of application of waste-heat boilers to trailing suction hopper dredgers. Using results of own operational research on dredgers this author determined thermal power demand for six hypothetical trailing suction hopper dredgers of various size, at accounting for a type of power system and kind of fuel combusted by dredger's power plant. By means of basic indices of...
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Determination of heat transfer coefficient in evaporator of the organic Rankine cycle using the Wilson method.
PublikacjaW pracy zastosowano metodę Wilsona do wyznaczania współczynnika przejmowania ciepła. Przedmiotem rozważań jest płytowy wymiennik ciepła pracujący jako parownik w laboratoryjnym stanowisku realizującym obieg ORC. Wykorzystana metoda jest metodą wydajną w przypadku wymienników ciepła o złożonej geometrii i dużej liczbie kanałów, dla których pomiar temperatury ścianki jest niemożliwy, a przez to określenie współczynników przejmowania...
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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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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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Correlation between Compressive Strength and Heat of Hydration of Cement Mortars with Siliceous Fly Ash
PublikacjaThis paper presents the results of calorimetric and strength tests of mortars with ordinary Portland cement and two substitution rates (10 and 20%) of cement by siliceous fly ash. The prepared samples were cured under isothermal conditions at four different temperatures: 23, 33, 43 and 53 °C. Heat of hydration was measured using an isothermal calorimeter dedicated to monitor the hydration process of cementitious composites such...