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Wyszukujesz frazę "Heat transfer" wg kryterium: Temat


Tytuł:
Analysis of heat and mass transfer in an adsorption bed using CFD methods
Autorzy:
Janusz, Szymon
Szudarek, Maciej
Rudniak, Leszek
Borcuch, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/27312232.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
heat transfer
adsorption
CFD
mass transfer
refrigeration devices
Opis:
The trend of reducing electricity consumption and environmental protection has contributed to the development of refrigeration technologies based on the thermal effect of adsorption. This article proposes a methodology for conducting numerical simulations of the adsorption and desorption processes. Experimental data available in the literature were used as guidelines for building and verifying the model, and the calculations were carried out using commercial computational fluid dynamics software. The simulation results determined the amount of water vapor absorbed by the adsorbent bed and the heat generated during the adsorption process. Throughout the adsorption process, the inlet water vapor velocity, temperature, and pressure in the adsorbent bed were monitored and recorded. The results obtained were consistent with the theory in the literature and will serve as the basis for further, independent experimental studies. The validated model allowed for the analysis of the effect of cooling water temperature on the sorption capacity of the material and the effect of heating water temperature on bed regeneration. The proposed approach can be useful in analyzing adsorption processes in refrigeration applications and designing heat and mass exchangers used in adsorption systems.
Źródło:
Archives of Thermodynamics; 2023, 44, 2; 177--194
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mixed convection heat transfer in trapezoidal lid-driven cavity with uniformly heated inner circular cylinder
Autorzy:
Hussein, Asmaa Ali
Powiązania:
https://bibliotekanauki.pl/articles/27312211.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
cavity
heat transfer
mixed convection
lid-driven
Opis:
The present work comprises a numerical analysis using the Ansys program to solve the problem of combined free-forced convection around a circular cylinder located in a horizontal lid-driven trapezoidal enclosure. The enclosure is filled with water. The upper moving wall and lower fixed wall are cold at a constant temperature, whereas the inclined walls are adiabatically insulated. The uniformly heated cylinder is located at different positions in the cavity. The study covers three values of Richardson number (0.01, 1, and 10). The results show that the streamlines and isotherms in the enclosure, the Nusselt number and friction factor in the moving wall, hot wall and bottom wall are strongly dependent on the position of the inner hot cylinder. The results are validated with previous work, and the comparison gives good agreement.
Źródło:
Archives of Thermodynamics; 2023, 44, 3; 99--118
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical model and measurements of a combi-steamer condensation hood
Autorzy:
Tokarski, Mieszko
Ryfa, Arkadiusz
Buliński, Piotr
Rojczyk, Marek
Ziarko, Krzysztof
Nowak, Andrzej J.
Powiązania:
https://bibliotekanauki.pl/articles/240444.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
energy balance
heat transfer
heat exchanger
condensation
condensation hood
Opis:
Combi-steamer condensation hoods are widely used in modern gastronomy. They condense steam produced by the combi-steamer and also filter solid particles, moisture, grease and smells. All these factors negatively affect the staff and dishes, so efficient work of the condensation hoods becomes important. A mathematical and experimental analysis of such a device is described in this paper. First a measurement methodology was designed and measurements of air humidity, temperature and mass flow rates were performed. The measurement procedure concerned dedicated a steam generator and combi-steamer. Next a mathematical model was developed. It was based on mass and energy balances of the condensation hood. The condensate flow rate turned out to be insufficient to fulfill the energy balance while measured directly. Hence, it was calculated from heater’s power of the steam generator and the balance model was validated. The combisteamer had an unknown output, so the condensate flow rate was provided by the balance model after its validation. A preliminary diagnosis of the device was carried out as well.
Źródło:
Archives of Thermodynamics; 2020, 41, 1; 125-149
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of thermal-flow characteristics of the minichannel heat exchanger of variable louvers height
Autorzy:
Romaniak, Artur
Kowalczyk, Michał Jan
Łęcki, Marcin
Gutkowski, Artur
Górecki, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/27312209.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
CFD
heat transfer
heat pump
louvered fin
minichannel heat exchanger
Opis:
The numerical simulation of the heat transfer in the flow channels of the minichannel heat exchanger was carried out. The applied model was validated on the experimental stand of an air heat pump. The influence of louver heights was investigated in the range from 0 mm (plain fin) to 7 mm (maximum height). The set of simulations was prepared in Ansys CFX. The research was carried out in a range of air inlet velocities from 1 to 5 m/s. The values of the Reynolds number achieved in the experimental tests ranged from 93 to 486. The dimensionless factors, the Colburn factor and friction factor, were calculated to evaluate heat transfer and pressure loss, respectively. The effectiveness of each louver height was evaluated using the parameter that relates to the heat transfer and the pressure drop in the airflow. The highest value of effectiveness (1.53) was achieved by the louver height of 7 mm for the Reynolds number of around 290.
Źródło:
Archives of Thermodynamics; 2023, 44, 3; 119--141
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of photovoltaic panel cooling beneath a single nozzle based on a configurations framework
Autorzy:
Mzad, Hocine
Otmani, Abdessalam
Powiązania:
https://bibliotekanauki.pl/articles/1845494.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
photovoltaic panel
nozzle
dispersion
comsol
glazing
heat transfer
Opis:
Solar cell performance decreases with increasing temperature, heat can reduce output efficiency by 10–25%. The operating temperature plays a key role in the photovoltaic conversion process. Increase in electrical efficiency depends on cooling techniques, in particular photovoltaic modules installed in the high temperature regions. A cooling process using a single nozzle of photovoltaic panel operating under different configurations was simulated. The simulation contains two parts: the first is a thermodynamic investigation of fluid impingement upon the sensor front face. The second is a performance comparison between two types of glass cover. The major result that emerges from this simulation is the effect of a single nozzle arrangement to enhance the cooling process, under a low cadence of impinging droplets in the range 0.1–1.7 m/s.
Źródło:
Archives of Thermodynamics; 2021, 42, 1; 115-128
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat transfer coefficient measurements on curved surfaces
Autorzy:
Kurowski, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/1845471.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heat transfer coefficient
measurements
methodology
gas turbine
cooling
Opis:
This paper presents the results of experimental research on heat transfer distribution under the impinging jets at high jet velocity on curved surfaces. The air jets flow out from the common pipe and impinge on a surface which is cooled by them, in this way all together create a model of external cooling system of low pressure gas turbine casing. Preliminary measurement results from the flat plate case were compared with the results from the curved surface case. Surface modification presented in this paper relied on geometry change of flat surface to the form of a ‘bump’. The special system of pivoted mirrors was implemented during the measurements to capture the heat exchange on curved surfaces of the bump. The higher values of mean heat transfer coefficient were observed for all flow cases with a bump in relation to the reference flow case with a flat plate.
Źródło:
Archives of Thermodynamics; 2021, 42, 2; 155-170
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat transfer in falling film evaporators during the industrial process of apple juice concentrate production
Autorzy:
Cyklis, P.
Powiązania:
https://bibliotekanauki.pl/articles/240517.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heat transfer
falling film evaporator
industrial
transport
ciepło
przemysł
Opis:
Falling film, shell-tube type evaporators are commonly used heat exchangers for the production of fruit juice concentrate. The main problem in the design of the exchanger is a reliable estimation of wall heat transfer coefficients for all effects in real operating conditions. Most literature sources for the overall heat transfer coefficients are based on laboratory measurements, where the tubes are usually short, no fouling exists and the flow rate is carefully adjusted. This paper shows the heat transfer estimated in real industrial operating conditions, compared to literature sources. Paper is based on the author’s own experience in designing and launching several evaporators for juice concentrate production into operation. As a summary, the design heat transfer coefficients are provided with relation to sugar content in juice concentrate.
Źródło:
Archives of Thermodynamics; 2018, 39, 3; 3-13
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computational fluid dynamics simulation of heat transfer from densely packed gold nanoparticles to isotropic media
Autorzy:
Radomski, Piotr
Ziółkowski, Paweł
de Sio, Luciano
Mikielewicz, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/1954995.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heat transfer
gold nanoparticles
glasses
polymers
computational fluid dynamics
Opis:
This work aims to determine and compare heat generation and propagation of densely packed gold nanoparticles (Au NPs) induced by a resonant laser beam (532 nm) according to the Mie theory. The heat flux propagation is transferred into the materials, which here are: silica glass; soda-lime-silica glass; borosilicate glass; polymethyl methacrylate (PMMA); polycarbonate (PC); and polydimetylosiloxane (PDMS). This analysis aims to select the optimum material serving as a base for using photo-thermoablation. On the other hand, research focused only on Newtonian heat transfer in gold, not on non-Fourier ones, like the Cattaneo approach. As a simulation tool, a computational fluid dynamics code with the second-order upwind algorithm is selected. Results reveal a near-Gaussian and Gaussian temperature distribution profile during the heating and cooling processes, respectively. Dependence between the maximum temperature after irradiation and the glass thermal conductivity is observed confirming the Fourier law. Due to the maximum heating area, the borosilicate or soda-lime glass, which serves as a base, shall represent an excellent candidate for future experiments.
Źródło:
Archives of Thermodynamics; 2021, 42, 3; 87-113
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of heat transfer correlation on wet cylinder liner temperature distribution when converting an old engine into a turbocharged engine
Autorzy:
Trung, Kien Nguyen
Powiązania:
https://bibliotekanauki.pl/articles/1955004.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heat transfer
correlation
turbocharged engine
cylinder liner
distribution
Supercharging
Opis:
For conventional diesel engines, two of the most widely used global correlations are due to Woschni and Hohenberg. Besides, the modern diesel engines used a new heat transfer coefficient correlation was proposed by Finol and Robinson. In Vietnam, improving engine power density is a trend of improving non-turbocharged base engines by using a supercharging system with exhaust gas energy recovery. Increasing engine power by the turbocharger is limited for two reasons: mechanical stress and thermal stress of the components surrounding the combustion chamber. In general, the heat transfer coefficient has a major effect on heat transfer rate, especially during the combustion process. So, the purpose of this study is to compare the cylinder distribution results from the simulation using the equations of Woschni and Hohenberg and compare to the experiment results when converting an old heavy-duty engine into a turbocharged engine. Results show that the cylinder distribution using Hohenberg’s correlation has a good agreement with the experiment results, especially in the case of a turbocharged engine.
Źródło:
Archives of Thermodynamics; 2021, 42, 3; 159-172
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Innovative method for heat transfer enhancement through shell and coil side fluid flow in shell and helical coil heat exchanger
Autorzy:
Kumar, Rajesh
Chandra, Prakash
-, Prabhansu
Powiązania:
https://bibliotekanauki.pl/articles/949948.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
overall heat transfer coefficient
effectiveness
helical coil
pressure drop
Opis:
The effect of shell side and coil side volume flow rate on overall heat transfer coefficient, effectiveness, pressure drop and exergy loss of shell and helical coil heat exchanger were studied experimentally under steady state conditions. The working fluid, i.e., water was allowed to flow at three different flow rates of 1, 2, and 3 l/min on shell side (cold water) and at 1, 1.5, 2, 2.5, and 3 l/min on coil side (hot water) for each shell side flow rate at the temperatures of 298±0.4 K and 323±0.4 K, respectively. The results found that the overall heat transfer coefficient increased with increasing both shell side and coil side volume flow rates. The inner Nusselt number significantly increased with the coil side Dean number.
Źródło:
Archives of Thermodynamics; 2020, 41, 2; 239-256
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations on heat and momentum transfer in CuO-water nanofluid
Autorzy:
Dzido, G.
Drzazga, M.
Lemanowicz, M.
Gierczycki, A. T.
Powiązania:
https://bibliotekanauki.pl/articles/240561.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nanofluids
fluid mechanics
heat transfer
nanopłyny
mechanika płynów
przenikanie ciepła
Opis:
This paper presents results of investigations on the application of CuO-water nanofluids for intensification of convective heat transfer. Performance of nanofluids with 2.2 and 4.0 vol.% CuO NPs (nanoparticles) content were examined with regard to heat transfer coefficient and pressure losses in case of turbulent flow in a tube. Negligible impact of examined nanofluid on heat transfer improvement was found. Moreover, measured pressure losses significantly exceeded those determined for primary base liquid. The observations showed that application of nanofluid for heat transfer intensification with a relatively high solid load in the examined flow range is rather controversial.
Źródło:
Archives of Thermodynamics; 2015, 36, 2; 49-59
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A qualitative study of mixing a fluid inside a mechanical mixer with the effect of thermal buoyancy
Autorzy:
Hassouni, Souad
Laidoudi, Houssem
Makinde, Oluwole Daniel
Bouzit, Mohamed
Boumediene, Haddou
Powiązania:
https://bibliotekanauki.pl/articles/2204073.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mechanical agitation
mixing process
heat transfer
thermal buoyancy
power number
Opis:
This paper is concerned with the rotational motion of the impeller and the thermal buoyancy within a mechanical mixer. The task was investigated numerically using the ANSYS-CFX simulator. The programmer is based on the finite volume method to solve the differential equations of fluid motion and heat transfer. The impeller has hot surfaces while the vessel has cold walls. The rotational movement of the impeller was controlled by the Reynolds number, while the intensity of the thermal buoyancy effect was controlled by the Richardson number. The equations were solved for a steady flow. After analyzing the results of this research, we were able to conclude that there is no effect of the values of Richardson number on the power number. Also, with the presence of the thermal buoyancy effect, the quality of the fluid mixing becomes more important. The increasing Richardson number increases the value of the Nusselt number of the impeller.
Źródło:
Archives of Thermodynamics; 2023, 44, 1; 105--119
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigation of single-phase microjet cooling of microelectronics
Autorzy:
Rusowicz, A.
Leszczyński, M.
Grzebielec, A.
Laskowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/240614.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cooling
heat transfer
microjets
microprocessor
chłodzenie
wymiana ciepła
mikrojety
mikroprocesor
Opis:
Development of electronics, which aims to improve the functionality of electronic devices, aims at increasing the packing of transistors in a chip and boosting clock speed (the number of elementary operations per second). While pursuing this objective, one encounters the growing problem of thermal nature. Each switching of the logic state at the elementary level of an integrated circuit is associated with the generation of heat. Due to a large number of transistors and high clock speeds, higher heat flux is emitted by the microprocessor to a level where the component needs to be intensively cooled, or otherwise it will become overheated. This paper presents the cooling of microelectronic components using microjets.
Źródło:
Archives of Thermodynamics; 2015, 36, 3; 139-147
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study of car radiator using dimple roughness and nanofluid
Autorzy:
Thapa, Robin Kumar
Bisht, Vijay Singh
Bhandari, Prabhakar
Rawat, Kamal Singh
Powiązania:
https://bibliotekanauki.pl/articles/2134933.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heat transfer
augmentation
nanofluid
pumping power
car radiator
artificial roughness
Opis:
Thermal augmentation in flat tube of car radiator using different nanofluids has been performed more often, but use of artificial roughness has been seldom done. Artificial roughness in the form of dimple is used in the present research work. Present study shows the impact of dimple shaped roughness and nanofluid (Al2O3/pure water) on the performance of car radiator. The pitch of dimples is kept at 15 mm (constant) for all the studies performed. The Reynolds number of the flow is selected in the turbulent regime ranging from 9350 to 23 000 and the concentration of the nanofluid is taken in the range of 0.1–1%. It has been found that the heat transfer rate has improved significantly in dimpled radiator tube on the expense of pumping power. Furthermore, the heat transfer rate also increases with increase in nanoparticle concentration from 0.1% to 1.0%. The highest heat transfer enhancement of 79% is observed at Reynolds number 9350, while least enhancement of 18% is observed for Reynolds number of 23 000.
Źródło:
Archives of Thermodynamics; 2022, 43, 3; 125--140
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental research on the resistojet thruster heater
Autorzy:
Kindracki, J.
Mężyk, J.
Paszkiewicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/240186.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
resistojet thruster
electric heater
heat transfer
grzałka elektryczna
transport ciepła
Opis:
The paper describes experimental research on a resistojet type rocket thruster which was built as an actuator in the Attitude Control System of a model space robotic platform. A key element of the thruster is the heater responsible for increasing the temperature of the working medium in the thruster chamber and hence the specific impulse. This parameter describes the performance of the thruster, increases providing – for lower propellant consumption – the same propulsion effect (thrust). A high performance thruster means either total launch mass can be reduced or satellite lifetime increased, which are key commercial factors. During the first phase of the project, 7 different heating chamber designs were examined. The heater is made of resistive wire with resistivity of 9Ω/m. Power is delivered by a dedicated supply system based on supercapacitors with output voltage regulated in the range of 20–70 V. The experimental phase was followed by designing the chamber geometry and the heating element able to deliver both: maximum increase of gas temperature and minimum construction dimensions. Experiments with the optimal design show an increase in temperature of the working gas (air) by about 300 °C giving a 40% increase in specific impulse. The final effect of that is a 40% reduction in mass flow rate while retaining thrust at a nominal level of 1 N.
Źródło:
Archives of Thermodynamics; 2018, 39, 3; 29-43
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł

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