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Wyszukujesz frazę "przepływ ciepła" wg kryterium: Temat


Wyświetlanie 1-9 z 9
Tytuł:
Opory przepływu, transport ciepła i masy dla trójkątnych wypełnień krótkokanałowych. Badania eksperymentalne
Flow resistance, heat and mass transfer for triangular short-channel structures. Experiments
Autorzy:
Iwaniszyn, M.
Ochońska, J.
Łojewska, J.
Janus, B.
Kleszcz, T.
Kołodziej, A.
Powiązania:
https://bibliotekanauki.pl/articles/306171.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Inżynierii Chemicznej PAN
Tematy:
trójkątna struktura krótkokanałowa
transport ciepła i masy
przepływ laminarny
Opis:
Trójkątne struktury krótkokanałowe są bardzo krótkimi monolitami o kształcie przekroju poprzecznego kanału zbliżonym do trójkąta równobocznego. Długość kanału struktury jest na tyle krótka, że w przeważającej jego części, występuje rozwijający się przepływ laminarny. Zjawisko to powoduje znaczny wzrost współczynników wnikania ciepła i masy, ale też wzrost oporów przepływu w porównaniu z klasycznymi monolitami o długich kanałach. Podczas pomiarów wnikania ciepła struktury krótkokanałowe były ogrzewane płynącym przez nie prądem elektrycznym. W celu uzyskania rozwiązania dla transportu masy zastosowano analogię transportu ciepła i masy dla przepływu laminarnego. Opory przepływu mierzono przy pomocy mikromanometru Recknagla i miernika elektronicznego. Wyniki otrzymane dla struktur trójkątnych porównano z najczęściej używanymi monolitami ceramicznymi i złożem ziaren usypanych.
Triangular short-channel structures are very short monoliths of triangular cross-sectional channel shape. The length of the channel structure is so short, that for the most part of the channel, the developing laminar flow occurs. This phenomenon leads to highly enhanced heat and mass transfer, but the flow resistance is increased as well compared with classic long channel monoliths. During the heat transfer experiments the structures were heated by strong electric current flowing directly through them. The heat transfer experimental results were transformed to the mass transfer representation using heat and mass transfer analogy for the laminar flow. The flow resistance was measured using the Recknagel micromanometer and electronic indicator. The results obtained for the triangular structures were compared with the commonly used ceramic monolith and packed bed.
Źródło:
Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk; 2011, 15; 93-106
1509-0760
Pojawia się w:
Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical modeling of heat and mass transfer in cylindrical ducts
Autorzy:
Duda, P.
Mazurkiewicz, G.
Powiązania:
https://bibliotekanauki.pl/articles/240939.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
obliczenia numeryczne
przepływ burzliwy
przepływ laminarny
wymiana ciepła
Graetz problem
heat transfer
laminar and turbulent flow
numerical solution
Opis:
In this work, numerical modeling of steady state heat and mass transfer is presented. Both laminar and hydrodynamically fully developed turbulent flow in a pipe are shown. Numerical results are compared with values obtained from analytical solution of such problems. The problems under consideration are often denoted as extended Graetz problems. They occur in heat exchangers using liquid metals as working fluid, in cooling systems for electric components or in chemical process lines. Calculations were carried out gradually decreasing the mesh size in order to examine the convergence of numerical method to analytical solution.
Źródło:
Archives of Thermodynamics; 2010, 31, 1; 33-43
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Conjugate Heat Transfer in Electromagnetic Liquid Metal Dream Pipe
Autorzy:
Puvaneswari, P.
Shailendhra, K.
Powiązania:
https://bibliotekanauki.pl/articles/140031.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
enhancement of heat transfer
dream pipe
conjugate heat transfer
laminar flow
oscillatory flow
hydromagnetic flow
liquid metals
zwiększenie przepływu ciepła
rura typu dream-pipe
sprzężona wymiana ciepła
przepływ laminarny
przepływ oscylacyjny
przepływ hydromagnetyczny
metale ciekłe
Opis:
The combined effect of conjugation, external magnetic field and oscillation on the enhancement of heat transfer in the laminar flow of liquid metals between parallel plate channels is analyzed. In order to make our results useful to the design engineers, we have considered here only the wall materials that are widely employed in liquid metal heat exchangers. Indeed, all the results obtained through this mathematical investigation are in excellent agreement with the available experimental results. The effective thermal diffusivity κe is increased by 3 · 106 times due to oscillation and that the heat flux as high as 1.5 · 1010 (W/m2) can be achieved. Based on our investigation, we have recommended the best choice of liquid metal heat carrier, wall material and its optimum thickness along with the optimum value of the frequency to maximize the heat transfer rate. At the optimum frequency, by choosing a wall of high thermal conductivity and optimum thickness, an increase of 19.98% in κe can be achieved. Our results are directly relevant to the design of a heat transfer device known as electromagnetic dream pipe which is a very recent development.
Źródło:
Archive of Mechanical Engineering; 2017, LXIV, 3; 375-399
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation on the effects of obstruction and side ratio on non-Newtonian fluid flow behavior around a rectangular barrier
Autorzy:
Noferesti, Sara
Ghassemi, Hassan
Nowruzi, Hashem
Powiązania:
https://bibliotekanauki.pl/articles/122461.pdf
Data publikacji:
2019
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
non-Newtonian fluids
heat transfer
finite volume method
laminar flow
płyn nieniutonowski
przenikanie ciepła
wymiana ciepła
metoda objętości skończonej
przepływ laminarny
Opis:
In this paper, the characteristics of the flow and forced heat transfer of power law non-Newtonian fluids that flow around a quadrilateral and rectangular cylinder that are located in a 2D channel are investigated by use of the finite volume method (FVM) in a steady state flow regime. To this accomplishment, in the constant temperature, the effects of a different obstruction ratio, aspect ratio and Reynolds number are investigated. The Reynolds number in the range 5 ≤ Re ≤ 40, the power index in the range 0.5 ≤ n ≤ 1.4, the aspect ratio in the range 0.5 ≤ a ≤ 2, and the obstruction ratio in the range 0.125 ≤ b ≤ 0.5 were selected. By surveying the drag coefficient profiles, it’s concluded that as the obstruction ratio increases, the drag coefficient is increased, while an increase in the Reynolds number causes the lower drag coefficient. In addition, the drag coefficient is strongly increased by aspect ratio enhancements.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2019, 18, 1; 53-67
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study on thermal performance of water flow in a twisted duct heat exchanger
Autorzy:
Rashed, Musaab K.
Jehhef, Kadhum Audaa
Badawy, Faris Ali
Powiązania:
https://bibliotekanauki.pl/articles/2174205.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
konwekcja mieszana
wymiennik ciepła
przepływ laminarny
mixed convection
twisted square duct
heat exchanger
laminar flow
Opis:
This paper presents a numerical study of heat transfer through a downstream annulus using water as the working fluid within the laminar flow region. The annulus consisted of an outer twisted square duct and an inner circular pipe. A three-dimensional formulation was used to solve the Navier-Stokes equations numerically for the laminar flow system with a low Reynolds number. Three parameters were used in the numerical simulation: the length of the twisted square [...] the inner diameter of the inner circular pipe [...] and 25 mm and the twist angle [...]. Numerical calculations were conducted on sixteen twisted square duct heat exchangers, with water flowing within a Reynolds number range of .220 1100− The results were illustrated as a profile of the thermal enhancement factor, the friction factor and the Nusselt number. The results show that the twisted outer duct of the heat exchanger can create a swirl flow along the length of the heat exchanger. It also caused a boundary layer separation-reattachment on the wall of the inner pipe. Moreover, an increase in the twist angle increased the Nusselt number by %,20 and the friction factor was also increased as the annular gap of the heat exchanger decreased.
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 2; 199--216
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of some parameters on the thermohydraulic characteristics of a channel heat exchanger with corrugated walls
Autorzy:
Ameur, Houari
Sahel, Djamel
Powiązania:
https://bibliotekanauki.pl/articles/95233.pdf
Data publikacji:
2019
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
heat exchanger
corrugated walls
laminar flow
complex fluids
wymiennik ciepła
ściany pofalowane
przepływ laminarny
płyny złożone
Opis:
The present work is a numerical modeling of the flow of a viscous fluid provided with convective heat transfer in a rectangular channel. We focus on the influence of the shape of corrugations which are present on the channel walls. Three shapes of corrugations are studied and which are: the rectangular, triangular and semi-circular shape. Also, effects of the height and number of corrugations on the fluid dynamics and thermal characteristics of the exchanger are highlighted. The working fluid is non-Newtonian (having a shear thinning behavior modeled by the Otswald law). The obtained results reveal that the presence of corrugations yields a major change in the heat exchange execution. In terms of superiority of heat transfer ratio, the cases under investigation can be classified as follows: rectangular > triangular > semi-circular. However and in terms of low pressure drop, this ranking is reversed. Furthermore, the triangular and semicircular shapes were found to have almost similar effects.
Źródło:
Journal of Mechanical and Energy Engineering; 2019, 3, 1; 53-60
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical solutions of heat transfer for laminar flow in rectangular channels
Autorzy:
Rybiński, W.
Mikielewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/240574.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analytical solution
heat transfer
rectangular channel
laminar flow
fully developed
rozwiązanie analityczne
wymiana ciepła
kanał prostokątny
przepływ laminarny
Opis:
The paper presents two analytical solutions namely for Fanning friction factor and for Nusselt number of fully developed laminar fluid flow in straight mini channels with rectangular cross-section. This type of channels is common in mini- and microchannel heat exchangers. Analytical formulae, both for velocity and temperature profiles, were obtained in the explicit form of two terms. The first term is an asymptotic solution of laminar flow between parallel plates. The second one is a rapidly convergent series. This series becomes zero as the cross-section aspect ratio goes to infinity. This clear mathematical form is also inherited by the formulae for friction factor and Nusselt number. As the boundary conditions for velocity and temperature profiles no-slip and peripherally constant temperature with axially constant heat flux were assumed (H1 type). The velocity profile is assumed to be independent of the temperature profile. The assumption of constant temperature at the channel’s perimeter is related to the asymptotic case of channel’s wall thermal resistance: infinite in the axial direction and zero in the peripheral one. It represents typical conditions in a minichannel heat exchanger made of metal.
Źródło:
Archives of Thermodynamics; 2014, 35, 4; 29-42
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat transfer in helical coil heat exchanger:An experimental parametric study
Autorzy:
Kowalski, Krzysztof
Downarowicz, Dorota
Powiązania:
https://bibliotekanauki.pl/articles/185443.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
helical coil
heat exchanger
condensation
Wilson method
laminar flow
pressure drop
wymiennik ciepła
kondensacja
Metoda Wilsona
przepływ laminarny
Spadek ciśnienia
Opis:
Helical coil heat exchangers are widely used in a variety of industry applications such as refrigerationsystems, process plants and heat recovery. In this study, the effect of Reynolds number and theoperating temperature on heat transfer coefficients and pressure drop for laminar flow conditions wasinvestigated. Experiments were carried out in a shell and tube heat exchanger with a copper coiledpipe (4 mm ID, length of 1.7 m and coil pitch of 7.5 mm) in the temperature range from 243 to 273 K.Air – propan-2-ol vapor mixture and coolant (methylsilicone oil) flowed inside and around the coil,respectively. The fluid flow in the shell-side was kept constant, while in the coil it was varied from 6.6to 26.6 m/s (the Reynolds number below the critical value of 7600). Results showed that the helicalpipe provided higher heat transfer performance than a straight pipe with the same dimensions. Theconvective coefficients were determined using the Wilson method. The values for the coiled pipe werein the range of 3–40 W/m2·K. They increased with increasing the gas flow rate and decreasing thecoolant temperature.
Źródło:
Chemical and Process Engineering; 2019, 40, 1; 101--114
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unsteady three-dimensional MHD flow due to impulsive motion with heat and mass transfer past a stretching sheet in a saturated porous medium
Autorzy:
Rajagopal, K.
Veena, P. H.
Pravin, V. K.
Powiązania:
https://bibliotekanauki.pl/articles/264376.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
przepływ laminarny
naprężenia ścinające
wymiana ciepła
wymiana masy
unsteadiness
laminar flow
three dimensional
shear stress
heat and mass transfer
short-time and long-time solution
Opis:
The development of velocity, temperature and concentration fields of an incompressible viscous electrically conducting fluid, caused by impulsive stretching of the surface in two lateral directions and by suddenly increasing the surface temperature from that of the surrounding fluid in a saturated porous medium is studied. The partial differential equations governing the unsteady laminar boundary layer flow are solved analytically. For some particular cases, closed form solutions are obtained, and for large values of the independent variable asymptotic solutions are found. The surface shear stress in x and y directions and the surface heat transfer and surface mass transfer increase with the magnetic parameter and with permeability parameter and the stretching ratio, and there is a smooth transition from the short-time solution to the long-time solution.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 1; 137-151
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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