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Wyniki wyszukiwania dla: MINICHANNEL HEAT EXCHANGER
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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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An experimental investigation on the effect of new continuous core-baffle geometry on the mixed convection heat transfer in shell and coil heat exchanger
PublikacjaIn the article, the authors presented the influence of continuous core-baffle geometry at mixed convection heat transfer in shell and coil heat exchanger. Experiments were carried out for a large power range, i.e. from 100W to 1200W and mass flow rates ranging from 0.01 kg/s to 0.025 kg/s. During the experiments, the mass flow rate of cooling water, the temperature of water at the inlet and outlet as well as the wall temperature...
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A new construction of shell-and-tube heat exchanger with impinging jets and minichannels technologies for heat recovery from gases – experimental analysis
PublikacjaA dynamic development of technologies allowing waste heat utilization is observed in a correspondence with a pro-ecological approach of the zero waste idea. Such approach becomes the most demanding in the area of low-temperature was heat sources, especially gaseous media. Till now, they were usually not utilized due to unfavorable thermal conditions and high costs. Therefore, the zero waste approach directs research on techniques...
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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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Channel Blockage and Flow Maldistribution during Unsteady Flow in a Model Microchannel Plate heat Exchanger
PublikacjaThis paper describes the problem of channel blockage as a result of flow maldistribution between the channels of a model mini channel plate heat exchanger consisting of one pass on each leg. Each leg of the heat exchanger contains 51 parallel and rectangular minichannels of four hydraulic diameters namely 461 μm, 571 μm, 750 μm and 823 μm. In addition, a more complex geometry has been investigated where for the sake of breaking...
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Monitoring Regenerative Heat Exchanger in Steam Power Plant by Making Use of the Recurrent Neural Network
PublikacjaArtificial Intelligence algorithms are being increasingly used in industrial applications. Their important function is to support operation of diagnostic systems. This paper pesents a new approach to the monitoring of a regenerative heat exchanger in a steam power plant, which is based on a specific use of the Recurrent Neural Network (RNN). The proposed approach was tested using real data. This approach can be easily adapted to...
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Corrosion-erosion damage of heat exchanger tubes by desalted crude oil flowing at shell side
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Corrosion-erosion damage of heat exchanger tubes by desalted crude oil flowing at shell side.
PublikacjaRurki wymiennika zostały uszkodzone lokalnie przez odsoloną ropę naftową przepływającą pod ciśnieniem 2,6 MPa i w temperaturze 385-395K. Większość powierzchni rurek nie była uszkodzona i była pokryta osadem związków organicznych i nieorganicznych, zabezpieczającym przed uszkodzeniami. Badania wykluczyły możliwość występowania intensywnej korozji elektrochemicznej na powierzchniach rurek pozbawionych osadu. Przyczyną perforacji...
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Computational Fluid Dynamics and Experimental Studies of a New Mixing Element in a Static Mixer as a Heat Exchanger
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Thermal and economic investigation of straight and U-bend double tube heat exchanger with coiled wire turbulator
PublikacjaExperimental research has been carried out for four individual heat exchanger constructions, i.e., plain double tube, turbulized double tube, plain U-bend and U-bend with turbulator. Tests were made for the water-water system. The study covered a wide measuring range, i.e., Re = 800–9000 – on the shell side, for a constant cold water temperature of 9 ◦C and hot water of 50 ◦C. The heat exchangers were made from copper tubes with...
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Experimental investigation on straight and u-bend double tube heat exchanger with active and passive enhancement methods
PublikacjaAuthors in this work want to demonstrate the possibility to increase the heat transfer efficiency by using simple wire coil inserts to create turbulent flow in the boundary layer as well as air blowing into the annulus of the pipe. In the study, Wilson plot approach was applied in order to estimate heat transfer coefficients for all heat exchanger (HX) configurations. The study focuses on experimental values of heat transfer coefficient...
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Thermal Design of Double Pipe Heat Exchanger Used as an Oil Cooler in Ships: A Comparative Case Study
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Synergistic effects of a swirl generator and MXene/ water nanofluids used in a heat exchanger pipe of a negative CO2 emission gas power plant
Publikacjafocus on optimizing heat exchangers contributes to improved temperature control mechanisms, ensuring the sustainable operation of innovative power plants working towards negative CO2 emissions. In the realm of oxy-combustion within Negative CO2 Emission Power Plants (nCO2PP), the temperature of combustion products surpasses 3000 (K). Addressing this challenge, the imperative arises to reduce these elevated temperatures to a manageable...
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Selected aspects of two-phase flow studies using different visualization techniques in minichannels
PublikacjaThe subject of the study is to present the possibility of the use of visualization techniques in the researches on two-phase flows, carried out by the authors for many years. These works included as follows: heat transfer during the flow boiling, boiling crises and condensation in flow. The issue of the heat transfer intensification during the flow boiling through the channels of small diameters was analyzed. All this work focused...
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CHARAKTERYSTYKA WYMIANY CIEPŁA I OPORÓW PRZEPŁYWU OMYWANIA MIKROSTRUGAMI ROZWINIĘTEJ POWIERZCHNI
PublikacjaW 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...
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Analytical and reliability data from the real-time simulator biogas plant
Dane BadawczeThe dataset represents the results of biogas plant simulation. The described plant is an agricultural biogas system, which can produce electrical energy with power estimated up to 1070 kW and heat energy that can reach 1200 kW simultaneously.
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Testing an evaporator operation with a concave manifold, condenser temperature 30, evaporator temperature 70 and preheater temperature 60
Dane BadawczeThe experiment was conducted to test the evaporator operation. The heat exchanger was equipped with minigeometry (set of 50 parallel minichannels or single minigap). The studies were conducted for various mass flow rate of the working fluid and for various temperatures at the inlet of the evaporator. Accurate information about the test rig, the parameters...
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Testing an evaporator operation with a bifurcation manifold, condenser temperature 20 and evaporator temperature 85
Dane BadawczeThe experiment was conducted to test the evaporator operation. The heat exchanger was equipped with minigeometry (set of 50 parallel minichannels or single minigap). The studies were conducted for various mass flow rate of the working fluid and for various temperatures at the inlet of the evaporator. Accurate information about the test rig, the parameters...
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Testing an evaporator operation with a concave manifold, condenser temperature 30, evaporator temperature 70 and preheater temperature 40
Dane BadawczeThe experiment was conducted to test the evaporator operation. The heat exchanger was equipped with minigeometry (set of 50 parallel minichannels or single minigap). The studies were conducted for various mass flow rate of the working fluid and for various temperatures at the inlet of the evaporator. Accurate information about the test rig, the parameters...
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Testing an evaporator operation with a trapezoidal manifold, condenser temperature 90 and evaporator temperature 90
Dane BadawczeThe experiment was conducted to test the evaporator operation. The heat exchanger was equipped with minigeometry (set of 50 parallel minichannels or single minigap). The studies were conducted for various mass flow rate of the working fluid and for various temperatures at the inlet of the evaporator. Accurate information about the test rig, the parameters...
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Testing an evaporator operation with a bifurcation manifold, condenser temperature 20 and evaporator temperature 70
Dane BadawczeThe experiment was conducted to test the evaporator operation. The heat exchanger was equipped with minigeometry (set of 50 parallel minichannels or single minigap). The studies were conducted for various mass flow rate of the working fluid and for various temperatures at the inlet of the evaporator. Accurate information about the test rig, the parameters...
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Testing an evaporator operation with a rectangular manifold, condenser temperature 30 and evaporator temperature 90
Dane BadawczeThe experiment was conducted to test the evaporator operation. The heat exchanger was equipped with minigeometry (set of 50 parallel minichannels or single minigap). The studies were conducted for various mass flow rate of the working fluid and for various temperatures at the inlet of the evaporator. Accurate information about the test rig, the parameters...
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Testing an evaporator operation with a trapezoidal manifold, condenser temperature 70 and evaporator temperature 60
Dane BadawczeThe experiment was conducted to test the evaporator operation. The heat exchanger was equipped with minigeometry (set of 50 parallel minichannels or single minigap). The studies were conducted for various mass flow rate of the working fluid and for various temperatures at the inlet of the evaporator. Accurate information about the test rig, the parameters...
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Testing an evaporator operation with a bifurcation manifold, condenser temperature 20 and evaporator temperature 95
Dane BadawczeThe experiment was conducted to test the evaporator operation. The heat exchanger was equipped with minigeometry (set of 50 parallel minichannels or single minigap). The studies were conducted for various mass flow rate of the working fluid and for various temperatures at the inlet of the evaporator. Accurate information about the test rig, the parameters...
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Testing an evaporator operation with a bifurcation manifold, condenser temperature 20 and evaporator temperature 90
Dane BadawczeThe experiment was conducted to test the evaporator operation. The heat exchanger was equipped with minigeometry (set of 50 parallel minichannels or single minigap). The studies were conducted for various mass flow rate of the working fluid and for various temperatures at the inlet of the evaporator. Accurate information about the test rig, the parameters...
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INTENSYFIKACJA WYMIANY CIEPŁA W WYMIENNIKU WĘŻOWNICOWYM Z WYKORZYSTANIEM PRZEGRÓD O RÓŻNEJ GEOMETRII
PublikacjaW pracy zaprezentowano możliwości wykorzystania pasywnej intensyfikacji wymiany ciepła w postaci przegród dla podniesienia efektywności energetycznej wymiennika wężownicowego. Badania zostały przeprowadzone z wykorzystaniem modułowego wymiennika z wężownicą w postaci grzałki elektrycznej. Medium odbierającym ciepło była woda o stałych parametrach cieplnoprzepływowych na wlocie do modułu. Pomiary przeprowadzono dla szerokiego zakresu...
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Jan Wajs dr hab. inż.
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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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Wykorzystanie ciepła niskotemperaturowego do procesu suszenia peletu ze słomy z wykorzystaniem mikrostrugowego wymiennika ciepła
PublikacjaW artykule przedstawiono wpływ temperatury medium suszącego na zmiany względnej oraz bezwzględnej zawartości wilgoci podczas suszenia peletu ze słomy. Proces suszenia przeprowadzono przy stałym ciśnieniu atmosferycznym i różnych wartościach temperatury powietrza, jako czynnika suszącego, wynoszących odpowiednio: 40℃, 60℃, 80℃, 100℃ oraz 120℃. Badania eksperymentalne wykonywano na innowacyjnym stanowisku wyposażonym w mikrostrugowy...
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Applicability of arrays of microjets heat transfer correlations to design compact heat exchangers
PublikacjaThe 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
PublikacjaIn 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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Flow maldistribution and its mitigation in mini heat exchangers
PublikacjaIn the present paper, a detailed numerical investigation has been carried out to analyze the flow maldistribution in 50 parallel 1 mm x 1 mm rectangular minichannels and 1 mm depth minigap section with rectangular, trapezoidal, triangular or concave mani-folds in Z-type flow configuration (16 different cases). The working medium was ethanol and the mass flow rate was 5×10-4 kg/s. Both sections was heated from the bottom side. Heat...
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Thermohydraulic maldistribution reduction in mini heat exchangers
PublikacjaA detailed numerical investigation has been carried out to analyze the flow maldistribution in 50 parallel 1 mm × 1 mm rectangular minichannels and 1 mm depth minigap section with rectangular, trapezoidal, triangular or concave manifolds in Z-type flow configuration. The working medium was ethanol and the mass flow rate was 5 × 10−4 kg/s. Both sections were heated from the bottom side. Heat flux of 10 000 W/m2 and 5000 W/m2 was...
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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
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HEAT TRANSFER ENGINEERING
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Partition of friction heat between sliding semispaces due to adhesion-deformational heat generation
PublikacjaAnalytical expressions of heat-partition coefficient and contact temperatures for two sliding semispaces with account for adhesion-deformational heat generation and contact heat exchange have been obtained. The rate of deformational heat generation is assumed to decay exponentially with increase of distance from the interface. It has been shown that heat-generation configuration and the intensity of contact heat exchange have impact...
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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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Minichannel and minigap classification criteria based on the aspect ratio of the minigeometry: A numerical study
PublikacjaA detailed numerical investigation has been carried out to analyze the diabatic flow distribution and velocity profile in 18 minigeometries with various aspect ratios for V-type and I-type flow configurations (for 36 cases) assuming ethanol as a working fluid. The aim of the study is to distinguish the value of the aspect ratio for which the flow in minigeometry starts to be two-dimensional (minigap). Cases with a constant Reynolds...
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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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Experimental study of flow boiling pressure drop and heat transfer of R1233zd(E) at moderate and high saturation temperatures
PublikacjaThe paper presents the results of experimental study of flow boiling of R1233zd(E) in minichannel at moderate and high saturation temperatures. The heat transfer coefficient and pressure drop were measured for flow boiling in a stainless steel tube with 2 mm inside diameter and a length of 300 mm. Experiment has been conducted for saturation temperatures ranging from 83 to 145 °C which corresponds to values of reduced pressures...
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Experimental and Computational Fluid Dynamics Studies on Straight and U-Bend Double Tube Heat Exchangers with Active and Passive Enhancement Methods
PublikacjaIn this work, the authors wanted to demonstrate the possibility to increase the heat transfer efficiency by using simple wire coil inserts to create turbulent flow in the boundary layer as well as air blowing into the annulus of the pipe. Experimental investigations were carried out for four heat exchanger constructions, i.e., plain double tube, turbulized double tube, plain U-bend double tube, U-tube with turbulator, plain double...
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An advanced thermal-FSI approach of an evaporation of air heat pump
PublikacjaThe paper presents selected problems of numerical modeling of an advanced thermal-FSI approach of evaporator of air heat pomp. The example of a fin-tube evaporator has been studied, focusing on obtaining of heat exchanger characteristics applying two-phase flow model for the in-tube refrigerant flow. Special attention is given to heat transfer between separated medium for different air velocity and changed refrigerant mass flow...
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Parametric study of fluid flow and heat transfer over louvered fins of air heat pump evaporator
PublikacjaTwo-dimensional numerical investigations of the fluid flow and heat transfer have been carried out for the laminar flow of the louvered fin-plate heat exchanger, designed to work as an air-source heat pump evap- orator. The transferred heat and the pressure drop predicted by simulation have been compared with the corresponding experimental data taken from the literature. Two dimensional analyses of the louvered fins with varying...
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An inverse algorithm for contact heat conduction problems with an interfacial heat source based on a first-order thermocouple model
PublikacjaInverse problems of contact heat conduction with an interfacial heat source are common in various fields of science, engineering and technology. In this study, an algorithm for their solution is developed based on an inverse parametric optimisation method with an impulse response function describing the heat partition and contact heat transfer. A first-order thermocouple model with a time constant parameter is embedded in the impulse...
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Numerical methods in heat and fluid flow
Kursy OnlineThis course introduces numerical methods for solving complex problems in heat and fluid flow using computational tools such as ANSYS Fluent. Topics include geometry creation, meshing, steady and transient flow simulations, heat transfer, and turbulence modeling. The course emphasizes practical applications through exercises like laminar and turbulent flow, conjugate heat transfer, and combustion modeling, culminating in a final...
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Microjet technology as a perspective intensification method for high performance heat exchangers
PublikacjaIn 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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High-efficiency mini and micro heat exchangers for dispersed power generation
PublikacjaTaking into account the dispersed systems technologies and their development, the ORC systems seem to be promising technology amongst various micro-CHP domestic units (electrical power production below 10 kWe), however practical realization of the ORC cycle in a micro-scale is technically challenging. The system consists in devices such as the vapour generation unit (boiler), expansion device and heat exchangers. Each of them should...
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High-temperature heat pumps – potential technology for heat recovery and production of process heat
PublikacjaIn the paper, the high temperature vapour compressor based heat pump with a selection of working fluids, both perspective and ecological ones, is considered. Such system is not yet commercially available on the market and in author’s opinion it has significant potential for various applications. In the presented analysis it was assumed that the heat source has a temperature of 50oC and the temperature lift is 60, 80 and 100K respectively....
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Comparison of various flow maldistribution quantification methods in mini heat exchangers
PublikacjaThe aim of study is to compare various flow maldistribution quantification methods, using velocity, mass flow rate, pressure, and temperature. An experimentally validated numerical study has been prepared and a heat exchanger with 34 semi-circular channels with a diameter of 3.1 mm has been tested. The minichannels were heated from the bottom with a heat flux of 50, 60, 70, and 80 kW/m2. The cases for various inlet velocities of...
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Heat transfer and heat exchangers
Kursy OnlineOmówienie głównych mechanizmów i praw przenoszenia ciepła. Przykłady rozwiązywania zagadnień z przewodzenia ciepła, konwekcji i radiacji. Podstawy teorii rekuperatorów. Przykłady obliczania pół powierzchni rekuperatorów.