displaying 1000 best results Help
Search results for: heat tranfer
-
Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources
PublicationA 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...
-
Pressure drop related to flow maldistribution in a model minichannel plate heat exchanger
PublicationThe paper describes the issues related to the pressure drop that accompanies the phenomenon of maldistribution of working fluid between the channels of a model minichannel plate heat exchanger. The research concerns a single exchanger's plate containing 51 (in every geometry) parallel rectangular minichannels of hydraulic diameters 461 µm, 571 µm, 750 µm and 823 µm. In addition, the more complex geometry has been investigated,...
-
Underwater in situ local heat treatment by additional stitches for improving the weldability of steel
PublicationIn this paper the influence of in situ local heat treatment performed by additional stitches on the weldability of high-strength low-alloy (HSLA) S355J2C+N steel was tested. The investigated steel is characterized by high susceptibility to cold cracking. It is necessary to find a method to improve the quality of welded joints. The local heat treatment was applied as an eect of bead-on plate welding made on the face of a Tekken...
-
Effect of Flow Normalization in Micro-Pin-Finned Heat Sink: Numerical Study
PublicationThe micro-pin-fin heat sink (MPFHS) is widely employed for the heat transfer enhancement of microchannel heat sinks. In the current paper, the effect of flow normalization on the thermohydraulic performance of micro-pin-finned heat sinks is studied numerically. Two geometries of MPFHSs, the conventional design micro-pin-fin heat sink (CD-MPFHS) with a uniform-width micro pin fin and the proposed design micro-pin-fin heat sink (PD-MPFHS)...
-
Performance of the very high-temperature heat pump with low GWP working fluids
PublicationTraditional heat pumps are a very attractive pro-ecological solutions for a number of applications, including providing of heating or heat recovery from industrial processes. The application range of heat pumps could be greatly enlarged when the operating temperature would be increased to 130-150°C and/or the temperature lift can be increased to 50-100 K. In the paper, the very high temperature vapour-compressor based single stage...
-
THE THERMODYNAMIC ANALYSIS OF THE SZEWALSKI HIERARCHIC VAPOUR CYCLE COOPERATED WITH THE SYSTEM OF HEAT RECOVERY
PublicationIn this paper, thermodynamic analysis of the Szewalski hierarchic vapour cycle cooperated with the system of heat recovery from exhaust gases are presented. According to that purpose, the CFM (Computation Flow Mechanics [1,3]) approach has correctly been used. The whole system consists of the first traditional steam cycle, the second organic Rankine cycle (ORC) and system of heat recovery with use of water with temperature 90...
-
The Use of Liquid Crystal Thermography an Image Processing in Heat and Fluid-Flow Research
PublicationLiquid 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...
-
A simple approach to heat exchanger sizing optimisation by means of entrophy generation minimisation
PublicationIn 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...
-
Enhanced Electrochemical Performance of MnCo1.5Fe0.5O4Spinel for Oxygen Evolution Reaction through Heat Treatment
PublicationMnCo1.5Fe0.5O4 spinel oxide was synthesized using the sol−gel technique, followed by heat treatment at various temperatures (400, 600, 800, and 1000 °C). The prepared materials were examined as anode electrocatalysts for watersplitting systems in alkaline environments. Solid-state characterization methods, such as powder X-ray diffraction and X-ray absorption spectroscopy (XAS), were used to analyze the materials’ crystallographic...
-
A System for Heart Sounds Classification
PublicationThe 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,...
-
An innovative light child seat
PublicationPrzedstawiono rozwój konstrukcji i badania symulacyjne fotelika samochodowego do przewozu dziecka.
-
CHARAKTERYSTYKA WYMIANY CIEPŁA I OPORÓW PRZEPŁYWU OMYWANIA MIKROSTRUGAMI ROZWINIĘTEJ POWIERZCHNI
PublicationW artykule przedstawiono eksperymentalne badania kompaktowego wymiennika ciepła z intensyfikacją przejmowania ciepła przy użyciu mikrostrug. Niniejszy artykuł przedstawia projekt i testy prototypu, wymiennika ciepła typu mikrostrugowego. Modułowa konstrukcja wymiennika umożliwia zmianę wymiarów geometrycznych, a także zmianę materiału przegrody wymiennika ciepła. Metoda graficzna Wilsona została z zastosowana w celu określenia...
-
Nonradiative long range energy transfer in donor-acceptor systems with excluded volume
PublicationW pracy analizowano bezpromienisty długozasięgowy transfer energii w układach donor-akceptor z uwzględnieniem objętości wyłączonej. Stwierdzono, że zanik fluorescencji pierwotnie wzbudzonych donorów jest wolniejszy, jeżeli uwzględnia się objętość wyłączoną. Ten efekt jest znacznie wzmocniony, gdy akceptory znajdują się w pewnej objętości niedostępnej dla donorów. Analizę numeryczną przeprowadzono stosując metodę symulacji Monte...
-
International Journal on Software Tools for Technology Transfer
Journals -
Entropy Measures of heart rate variability for short ECG datasets in patients with congestive heart failure
PublicationWe 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...
-
Entropy measures of heart rate variability for short ECG datasets in patients with congestive heart failure
PublicationWe 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...
-
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment
Journals -
TEXAS HEART INSTITUTE JOURNAL
Journals -
Journal of the American Heart Association
Journals -
Journal of the Saudi Heart Association
Journals -
EUROPEAN JOURNAL OF HEART FAILURE
Journals -
Heart advisor / the Cleveland Clinic
Journals -
Current Heart Failure Reports
Journals -
JOURNAL OF HEART VALVE DISEASE
Journals -
Head and Neck Russian Journal
Journals -
Theory and Practice of Meat Processing
Journals -
JOURNAL OF HEART AND LUNG TRANSPLANTATION
Journals -
JOURNAL OF HEAD TRAUMA REHABILITATION
Journals -
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
PublicationSposób 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...
-
HEART AND VESSELS
Journals -
EEDI Impact for a Tanker
PublicationReferat przedstawia sposób analizy wskaźnika EEDI zgodnie z wymaganiami IMO-MEPC w zależności od parametrów głównych, prędkości, charakterystyk oporowych oraz układu napędu statku dla wybranego tankowca typu Aframax. W analizie uwzględniono, także układ wytwarzania mocy elektrycznej wraz z innymi układami pomocniczymi tankowca, które są odbiornikami wytwarzanej mocy.
-
Operation of the 900 MW power plant with the ORC supplied from three heat sources
PublicationThe 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...
-
AUGMENTATION OF THE CRITICAL HEAT FLUX IN WATER-Al2O3, WATER-TiO2 AND WATER-Cu NANOFLUIDS
PublicationThe 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...
-
Review of Small Gas Turbine Engines and Their Adaptation for Automotive Waste Heat Recovery Systems
Publication -
Analytical method for calculation of heat source temperature drop for the Organic Rankine Cycle application
PublicationIn the paper presented are considerations on the cooperation of the limited capacity heat source with the Organic Rankine Cycle unit. Usually the heat source providing thermal energy to the Organic Rankine Cycle (ORC) may have twofold characteristics. It can be in the form of a single phase fluid, i.e. as hot exhaust gas or hot liquid, or in some cases it may be available as a phase changing fluid, as for example, technological...
-
Pipeline system for heat transportation from nuclear power plant — An optimizing approach
Publication -
Numerical modeling of cross-flow heat exchanger for air-conditioning purposes in preliminary study.
PublicationPraca przedstawia wyniki obliczeń numerycznych krzyżowego płytowo-rurowego wymiennika ciepła przeznaczonego do celów klimatyzacyjnych w początkowym etapie jego projektowania.
-
Modifications of the heat source model in numerical analyses of the metal-cored arc welding process
Publication -
Study of Heat Source Model and Residual Stress Caused by Welding in GMAW of Al Alloy
Publication -
Analysis of possibility and purposefulness of application of waste-heat boilers to trailing suction hopper dredgers
PublicationThis 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...
-
The In-House Method of Manufacturing a Low-Cost Heat Pipe with Specified Thermophysical Properties and Geometry
PublicationVarious types of heat pipes are available to purchase off the shelf, from various manufacturers, but most of them have strictly defined geometry and technical parameters. However, when there is a need to use a heat pipe (HP) with an unusual size and shape or working conditions other than the standard ones, it becomes very costly to order them from manufacturers, especially in small quantities, and only a few producers are willing...
-
A study of jet impingement cooling enhancement by concave and convex heat sink shape modifications
PublicationThe rising demand for efficient cooling technologies is a strong driver of extensive research in this area. This trend is particularly strong in turbines and microprocessors technology. Presented study is focused on the jet impingement cooling concept, which is used in various configurations for many years. The potential of the heat sink shape modification is not yet fully explored. Available literature suggests that average Nusselt...
-
Influence of Cement Replacement with Sewage Sludge Ash (SSA) on the Heat of Hydration of Cement Mortar
PublicationThe amount of fly ash from the incineration of sewage sludge is increasing all over the world, and its utilization is becoming a serious environmental problem. In the study, a type of sewage sludge ash (SSA) collected directly from the municipal sewage treatment plant was used. Five levels of cement replacement (2.5%, 5%, 7.5%, 10% and 20%) and unchanged water-to-binder (w/b) ratio (0.55) were used. The purpose of the study was...
-
Challenges in operating and testing loop heat pipes in 500–700 K temperature ranges
PublicationThe potential applications of loop heat pipes (LHPs) are the nuclear power space systems, fuel cell thermal management systems, waste heat recovery systems, medium temperature electronic systems, medium temperature military systems, among others. Such applications usually operate in temperature ranges between 500–700 K, hence it is necessary to develop an LHP system that will meet this requirement. Such a thermal management device...
-
Influence of Heat Treatment Temperature on Fatigue Toughness in Medium-Carbon High-Strength Steels
PublicationCurrent research has demonstrated that the tempering temperature affects the martensitic transformation of medium-carbon high-strength steels. This temperature plays an important role in the final microstructure, percentage ratios of martensite to ferrite phases and, consequently, in the mechanical properties and the fatigue response. So far, the relationship between the martensitic tempering temperature and the cyclic deformation...
-
Effect of tube bundle arrangement on performance of shell-and-tube latent heat storage system
PublicationThis work presents the results of experimental investigation on charging and discharging of latent heat storage systems (LHSS) in the form of shell-and-tube heat exchangers with a variable arrays of the tube bundles. The tests included two tube arrangements – in-line and triangular (staggered), a variable number of tubes in a bundle, two pitch ratios, and different tube positions in a bundle. Three commercial products (LTP56, RT54HC,...
-
Correlation between Compressive Strength and Heat of Hydration of Cement Mortars with Siliceous Fly Ash
PublicationThis 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...
-
Two bacterial small heat shock proteins, IbpA and IbpB, form a functional heterodimer
PublicationSmall 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...
-
Technical and economic conditions of supplying residential consumers with heat from nuclear power plant
PublicationThe 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...
-
Analysis of energy recovery from surplus water pressure of municipal heat distribution network
Publication