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Wyszukujesz frazę "boiling heat transfer" wg kryterium: Temat


Tytuł:
Nucleate pool boiling heat transfer from small horizontal smooth tube bundles
Autorzy:
Krasowski, K.
Cieśliński, J.
Powiązania:
https://bibliotekanauki.pl/articles/175416.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
boiling heat transfer
smooth tube bundle
Opis:
Measurements of boiling heat transfer coefficients in water, methanol and refrigerant R141b are reported for the bundles of smooth tubes that represent a portion of a flooded-type evaporator. Each bundle contained 19 instrumented, electrically heated tubes in a staggered triangular-pitch layout. The effect of heat flux, tube pitch and operating pressure is studied in the paper. Bundle factor and bundle effect are discussed as well. A correlation for prediction of a bundle average heat transfer coefficient is proposed.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2011, 123; 85-97
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase change heat exchangers made of pin-fins for boiling enhancement
Autorzy:
Orman, Łukasz J.
Radek, Norbert
Pietraszek, Jacek
Gontarski, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/104110.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
boiling heat transfer
microfins
microstructure
wymiana ciepła
mikrowłókna
mikrostruktura
Opis:
The paper deals with the important issue of boiling heat transfer enhancement using mechanical treatment of the heater surface. The surface has been modified in such a way that microfins have been produced. The application of such a structure leads to highly increased heat fluxes in relation to the smooth surface as has been presented and discussed in the paper. The experiments including distilled water and ethyl alcohol on the horizontal copper samples of 3 cm diameter have been considered. The heat flux value of microfinned surface was even nine times higher than the heat flux dissipated from the smooth surface without any coating. It proves a considerable enhancement of boiling with the application of the mechanically treated surfaces of heat exchangers.
Źródło:
Quality Production Improvement - QPI; 2019, 1, 1; 433-439
2657-8603
Pojawia się w:
Quality Production Improvement - QPI
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boiling heat transfer phenomenon from an isolated nucleation center
Wymiana ciepła przy wrzeniu dla wyodrębionego centrum nukleacji
Autorzy:
Orman, Ł. J.
Powiązania:
https://bibliotekanauki.pl/articles/402086.pdf
Data publikacji:
2016
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
boiling heat transfer
nucleation center
wymiana ciepła przy wrzeniu
centrum nukleacji
Opis:
The paper discusses a method of boiling heat transfer investigation from a cavity of given geometrical dimensions. The testing method is described together with literature review on the subject. This experimental concept can be used to provide useful data on the creation and departure frequency of bubbles, thus giving more insight into the boiling phenomenon.
Źródło:
Structure and Environment; 2016, 8, 1; 59-63
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of flow boiling heat transfer in a rectangular minichannel using liquid crystal and infrared thermography
Autorzy:
Strąk, K.
Piasecka, M.
Powiązania:
https://bibliotekanauki.pl/articles/175560.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
flow boiling heat transfer
rectangular minichannel
enhanced foil surface
liquid crystal thermography
infrared thermography
Opis:
This paper presents results of flow boiling heat transfer in two parallel asymmetrically heated vertical minichannels. The heating element for Fluorinert FC-72 flowing in the minichannels was a thin foil with an enhanced surface on the side in contact with the fluid. The channels were observed from both sides through glass panes. Two of the panes allowed us to observe the two phase flow patterns on the enhanced surface of the foil, while the other two panes were used for simultaneous measurement of temperature on the smooth side of the foil. The temperature was measured by applying two contactless methods. One was liquid crystal thermography (LCT), which required treating the foil surface with thermochromic liquid crystals (TLCs), and the other was infrared thermography (IRT), which required coating the foil surface with black paint. Calculations were performed on the basis ofa one-dimensional model to determine the heat transfer coefficient at the foil-fluid interface from the Robin boundary condition. The experimental results were graphically represented as the foil temperature and the heat transfer coefficient against the distance from the minichannel inlet and as LCT and IRT images obtained for saturated boiling.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2015, 128; 97-118
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pool Boiling Heat Transfer from Rough and Microstructure Coated Surfaces
Wymiana ciepła przy wrzeniu na powierzchniach chropowatych i z pokryciem mikrostrukturalnym
Autorzy:
Orman, Łukasz J.
Orman, Katarzyna
Wojton, Iwona
Powiązania:
https://bibliotekanauki.pl/articles/1811614.pdf
Data publikacji:
2020
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
boiling heat transfer
porous coatings
rough surface
wymiana ciepła przy wrzeniu
pokrycie porowate
chropowatość
Opis:
The paper presents the test results of pool boiling heat transfer on the rough surface and the surface covered with capillary – porous microstructure. The porous layer is made of copper fibers sintered in the reduction atmosphere. The volumetric porosity amounted to 68%, while its height 1 mm. Distilled water and ethyl alcohol were used as the working fluids. The experiments have been carried out under the atmospheric pressure. Enhancement of heat transfer in relation to the smooth reference surface has been recorded especially for the low range of superheats, which might be related to the density of active nucleation sites. Experimental results have been compared with selected models of boiling available in literature.
Artykuł przedstawia wyniki badań wymiany ciepła przy wrzeniu na powierzchniach chropowatych i z porowatym pokryciem metalowo-włóknistym. Mikrostruktura porowata została wykonana z włókien miedzianych spiekanych w atmosferze redukcyjnej. Porowatość objętościowa wynosi 68%, a wysokość warstwy 1 mm. Badania prowadzono dla wody destylowanej i alkoholu etylowego jako cieczy wrzących pod ciśnieniem atmosferycznym. Zaobserwowano intensyfikację wymiany ciepła w porównaniu do powierzchni gładkiej, szczególnie w zakresie małych przegrzań, co może być związane z gęstością aktywnych centrów nukleacji. Wyniki badań eksperymentalnych porównano z wybranymi modelami wrzenia dla danych powierzchni.
Źródło:
Rocznik Ochrona Środowiska; 2020, Tom 22, cz. 1; 514-525
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigation and characteristics of multiwalled carbon nanotube aqua nanofluids from a flat plate heater surface in a pool
Autorzy:
Vasudevan, D.
Senthil Kumar, D.
Murugesan, A.
Vijayakumar, C.
Powiązania:
https://bibliotekanauki.pl/articles/201185.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nanofluids
critical heat flux
heat transfer coefficient
boiling
heat transfer enhancement
Opis:
In this experimental investigation, the critical heat flux (CHF) of aqua-based multiwalled carbon nanotube (MWCNT) nanofluids at three different volumetric concentrations 0.2%, 0.6%, and 0.8% were prepared, and the test results were compared with deionized water. Different characterization techniques, including X-ray diffraction, scanning electron microscopy and Fourier transform infrared, were used to estimate the size, surface morphology, agglomeration size and chemical nature of MWCNT. The thermal conductivity and viscosity of the MWCNT at three different volumetric concentrations was measured at a different temperature, and results were compared with deionized water. Although, MWCNT-deionized water nanofluid showed superior performance in heat transfer coefficient as compared to the base fluid. However, the results proved that the critical heat flux is increased with an increase in concentrations of nanofluids.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 3; 547-554
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adjustment calculus and Trefftz functions applied to local heat transfer coefficient determination in a minichannel
Zastosowanie rachunku wyrównawczego i funkcji Trefftza do wyznaczenia lokalnego współczynnika przejmowania ciepła w minikanale
Autorzy:
Grysa, K.
Hożejowska, S.
Maciejewska, B.
Powiązania:
https://bibliotekanauki.pl/articles/281729.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
flow boiling
liquid crystals
heat transfer coefficient
Opis:
The paper presents results of numerical calculations conducted in order to define the heat transfer coefficient in flow boiling in a vertical minichannel with one side made of a heating foil with liquid crystals. During the experiment, we measured the local temperature of the foil, inlet and outlet liquid temperature and pressure, current and voltage drop of the electric power supplied to the heater. Local measurements of foil temperature were approximated with a linear combination of the Trefftz functions. The known temperature measurement errors allowed application of the adjustment calculus. The foil temperature distribution was determined by the FEM combined with the Trefftz functions. Local heat transfer coefficients between the foil and the boiling fluid were calculated from the third-kind condition.
Przedstawiono wyniki obliczeń numerycznych przeprowadzonych w celu określenia współczynnika przejmowania ciepła przy przepływie wrzącej cieczy w pionowym minikanale, którego jedna ściana wykonana jest z folii grzewczej pokrytej ciekłymi kryształami. Podczas eksperymentu mierzono: lokalną temperaturę folii, temperaturę cieczy na wlocie i wylocie z minikanału, ciśnienie cieczy w minikanale oraz spadek natężenia i napięcia prądu stałego dostarczanej do folii grzewczej. Lokalne pomiary temperatury folii aproksymowano kombinacją liniową funkcji Trefftza. Znane błędy pomiaru temperatury pozwoliły na stosowanie rachunku wyrównawczego. Rozkład temperatury folii został określony przy zastosowaniu MES w powiązaniu z funkcjami Trefftza. Lokalne współczynniki wymiany ciepła pomiędzy folią i wrzącym płynem zostały wyliczone z warunku trzeciego rodzaju.
Źródło:
Journal of Theoretical and Applied Mechanics; 2012, 50, 4; 1087-1096
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal stresses in the heated wall of the minichannel
Autorzy:
Błasiak, S.
Musiał, T.
Piasecka, M.
Strąk, K.
Powiązania:
https://bibliotekanauki.pl/articles/114583.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
thermal stress
distortion
minichannel
heat transfer
boiling
Opis:
This paper deals with thermal deformations of the heating foil in a heat exchanger with a rectangular minichannel. Flow boiling heat transfer was achieved to maximize the heat transfer coefficient. As confirmed by the experiments, the deformations resulting from the thermal expansion of the heating foil led to local narrowing of the channel, and consequently distorted flow and less effective heat transfer.
Źródło:
Measurement Automation Monitoring; 2016, 62, 1; 22-25
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation of pool nucleate boiling in nanofluid with lattice Boltzmann method
Autorzy:
Rostamzadeh, A.
Jafarpur, K.
Rad, E. G.
Powiązania:
https://bibliotekanauki.pl/articles/949317.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
pool boiling
nanofluid
lattice Boltzmann method
heat transfer
Opis:
Due to significant improvement of thermal performance and other properties of nanofluids, this group of liquids is in high demand. According to the literature, the effect of nanoparticles on boiling heat transfer enhancement or degradation is not the same among different investigations. In the present article, the pseudo-potential multiphase lattice Boltzmann method is used to simulate nucleate pool boiling with two different fluids: a pure liquid and a nanofluid. The current results indicate that the contact angle is the same for both the fluid and nanofluid when the vapor bubble detachment occurs. Also, bubble departure diameter is greater in the base liquid while bubble release frequency is higher in the nanofluid. In brief, the present results demonstrate that using a nanofluid instead of its base fluid will increase the boiling heat transfer coefficient.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 3; 811-825
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boiling in micro-channels
Autorzy:
Hetsroni, G.
Powiązania:
https://bibliotekanauki.pl/articles/199886.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
micro-channel
boiling
pressure drop
heat transfer
fluctuation
Opis:
Boiling heat transfer in micro-channels is a subject of intense academic and practical interest. Though many heat transfer correlations have been proposed, most were empirically formulated from experimental data. However, hydrodynamic and thermal aspects of boiling in micro-channels are not well understood. Moreover, there are only a few theoretical models that link the heat transfer mechanism with flow regimes in micro-channels. Also, there are discrepancies between different sets of published results, and heat transfer coefficients have either well exceeded, or fallen far below, those predicted for conventional channels. Here we consider these problems with regard to micro-channels with hydraulic diameters ranging roughly from 5 ěm to 500 ěm, to gain a better understanding of the distinct properties of the measurement techniques and uncertainties, the conditions under which the experimental results should be compared to analytical or numerical predictions, boiling phenomenon, as well as different types of micro-channel heat sinks. Two-phase flow maps and heat transfer prediction methods for vaporization in macro-channels are not applicable in micro-channels, because surface tension dominates the phenomena, rather than gravity forces. The models of convection boiling should correlate the frequencies, sizes and velocities of the bubbles and the coalescence processes, which control the flow pattern transitions, together with the heat flux and the mass flux. Therefore, the vapour bubble size distribution must be taken into account. The flow pattern in parallel micro-channels is quite different from that in a single micro-channel. At same values of heat and mass flux, different, time dependent, flow regimes occur in a given micro-channel. At low vapour quality, heat flux causes a sudden release of energy into the vapour bubble, which grows rapidly and occupies the entire channel cross section. The rapid bubble growth pushes the liquid-vapour interface on both caps of the vapour bubble, at the upstream and the downstream ends, and leads to a reverse flow. We term this phenomenon as explosive boiling. One of the limiting operating conditions with flow boiling is the critical heat flux (CHF). The CHF phenomenon is different from that observed in conventional size channels.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2010, 58, 1; 155-163
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation method for flow boiling and flow condensation of R134a and R1234yf in conventional and small diameter channels
Autorzy:
Mikielewicz, D.
Jakubowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/259535.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
heat transfer coefficient
flow boiling
conventional channels
minichannels
Opis:
The paper presents the results of calculations performed using the authors’ model to predict the heat transfer coefficient during flow boiling for two refrigerants R134a and R1234yf. The experimental data from various past studies have been collected and the calculations have been conducted for the 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 flow boiling and flow condensation model. The importance of taking into account the surface tension as the parameter exhibiting its importance in case of the flow in minichannels, as well as the influence of the reduced pressure were analysed. The obtained numerical results show good consistency with those recorded in the experiments.
Źródło:
Polish Maritime Research; 2017, S 1; 141-148
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fenomenologiczna ocena tworzenia się struktur wodno-olejowych podczas wrzenia w objętości
Phenomenological assessment of water-oil patterns formed during pool boiling
Autorzy:
Troniewski, L.
Filipczak, G.
Witczak, S.
Powiązania:
https://bibliotekanauki.pl/articles/2070619.pdf
Data publikacji:
2009
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
wrzenie w objętości
struktury wrzenia
wnikanie ciepła
pool boiling
boiling patterns
heat transfer
Opis:
W pracy przedstawiono wyniki badań i analiz dotyczących warunków wnikania ciepła podczas wrzenia mieszaniny cieczy wzajemnie nierozpuszczalnych. Eksperymenty przeprowadzono w dużej objętości i pod ciśnieniem atmosferycznym, wykorzystując jako czynniki robocze wodę oraz oleje o różnych właściwościach. Scharakteryzowano warunki wnikania ciepła przy różnej zawartości obu składników mieszaniny.
Experimental results of heat transfer during pool boiling of two immiscible liquids are presented. The experiments were carried out under atmospheric pressure. Water and various oil mixtures were used as working liquids. The conditions of heat transfer for a different content of both liquids in the mixture were characterized.
Źródło:
Inżynieria i Aparatura Chemiczna; 2009, 6; 188-189
0368-0827
Pojawia się w:
Inżynieria i Aparatura Chemiczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of the Specific Heat Flux During Boiling of the Dispersed Phase of the Emulsion
Autorzy:
Pavlenkо, Anatoliy
Koshlak, Hanna
Basok, Borys
Hrabova, Tatiana
Powiązania:
https://bibliotekanauki.pl/articles/27315739.pdf
Data publikacji:
2023
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
steam explosion
homogenisation
boiling
intensification of heat
mass transfer
Opis:
The intensity of heat exchange between the boiling emulsion and the enclosing surfaces is associated with the physical phenomena of the formation, growth, and destruction of vapour bubbles of the low-boiling component in the liquid phase. This article presents a methodology to assess the intensity of heat exchange processes. Using this technique, it is possible to predict the energy parameters of heat exchange equipment and the degree of intensification of heat transfer processes.
Źródło:
Rocznik Ochrona Środowiska; 2023, 25; 16--24
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An investigation into the influence of different parameters on the onset of boiling in minichannels
Autorzy:
Piasecka, M.
Powiązania:
https://bibliotekanauki.pl/articles/240757.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inicjacja wrzenia
przepływ wrzenia
wymiana ciepła
flow boiling
heat transfer
Incipience (onset) of boiling
Opis:
The paper presents experimental studies on boiling heat transfer in rectangular minichannels. The investigations focus on the transition from single phase forced convection to nucleate boiling, i.e., in the zone of boiling incipience. The experiment has been carried out with FC-72, R-123 and R-11 at the Reynolds number below 4700, corresponding to mass flow rate range 95-710 kg/(m s). The main part of the test section is a minichannel of pre-set depth from 0.7 to 2 mm and width (20, 40 and 60 mm), with different spatial orientations from vertical to horizontal and 30% inclination angle adjustment. The objective of the paper includes the impact of selected parameters (liquid flow velocity, pressure and inlet liquid subcooling, channel dimensions and spatial orientation) on the boiling incipience in minichannels. The investigations are intended to develop a correlation for the calculations of the Nusselt number under the conditions of boiling incipience in the minichannel as a function of changeable parameters.
Źródło:
Archives of Thermodynamics; 2012, 33, 4; 67-90
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of heat transfer during pool boiling on minifins surface coated with carbon nanotubes
Autorzy:
Strąk, E.
Pastuszko, R.
Kłosowiak, R.
Urbaniak, R.
Powiązania:
https://bibliotekanauki.pl/articles/175588.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pool boiling
carbon nanotube
heat transfer coefficient
power
electronic cooling
Opis:
The article describes the study of heat transfer during pool boiling on minifins surface coated with nanostructure. This is a molecular level technology used in engineering or mechanical factory. A surface with carbon nanotubes (CNTs) is highly effective in reducing the superheat incipience and enhancing both the heat flux and heat transfer coefficient. The paper focuses on the comparison of the surfaces, on which pool boiling heat transfer occurs, i.e., on minifins coated with carbon nanotubes (MF+N) with surfaces formed by sintering the woven copper wire mesh to the minifins tips (MF+M) and with plain minifins surface (MF). The experiments were carried out for two boiling fluids: water and ethyl alcohol. The purpose of the presented study was to find out which of those tested surfaces and fluids could be the best alternative for use in the cooling of electronic devices and which surfaces could be used as thermosyphon or heat pipe evaporator.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2015, 128; 59-72
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł

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