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    Wyświetlanie 1-28 z 28
    Tytuł:
    Analysis of transient natural convective flow of a nanofluid in a vertical tube
    Autorzy:
    Jha, Basant K.
    Chitumu, Ali J.
    Oni, Michael O.
    Powiązania:
    https://bibliotekanauki.pl/articles/1839829.pdf
    Data publikacji:
    2021
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    nanociecze
    naturalna konwekcja
    wymiana ciepła
    nanofluid
    transient
    natural convection
    heat transfer
    vertical tube
    Opis:
    An analysis into the transient natural convective flow of a nanofluid in a vertical tube is made. The governing equations of momentum, heat transfer and nanoparticle volume fraction are deduced, and the influence of the thermophoresis parameter and Brownian motion is incorporated. By direct integration and variation of the parameter, analytical solutions are obtained for flow formation and heat/mass transfer at steady-state. On the other hand, due to the complexity of same problem at transient state, a numerical solution is used to solve the discretized equations of motion using the implicit finite difference technique. The influence of the thermophoresis parameter and Brownian motion is noted and well discussed. For accuracy check, a numerical comparison is made between the steady state and transient state solution at large time; this comparison gives an excellent agreement. The role of various principal parameters on velocity profile, temperature, concentration of nanoparticles, Sherwood and Nusselt numbers are presented graphically and well discussed. It is noted that the buoyancy ratio decreases the fluid velocity significantly.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2021, 26, 2; 31-46
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Simulation of start-up behaviour of a passive autocatalytic hydrogen recombiner
    Autorzy:
    Rożeń, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/146233.pdf
    Data publikacji:
    2018
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    catalytic recombination
    computational fluid dynamics
    hydrogen safety
    natural convection
    rekombinacja katalityczna
    obliczeniowa dynamika płynów
    naturalna konwekcja
    Opis:
    Heterogeneous catalytic recombination of hydrogen with oxygen is one of the methods used to remove hydrogen from the containment of a light-water nuclear reactor (LWR). Inside a passive autocatalytic recombiner (PAR), hydrogen and oxygen molecules are adsorbed at catalyst active spots and they recombine to yield water. Heat released in this exothermic reaction creates natural convection of gas in the spaces between the elements supporting a catalyst. Hot and humid gas fl ows upwards into the PAR chimney, while fresh, hydrogen-rich gas enters the PAR from below. Catalytic recombination should start spontaneously at room temperature and low hydrogen concentration. Computational fl uid dynamics (CFD) has been used to study the dynamic behaviour of a plate-type Areva FR-380 recombiner in a quiescent environment for several test scenarios, including different rates of increase in hydrogen concentration and temporary catalyst deactivation. A method for the determination of pressure boundary conditions at the PAR exits was proposed and implemented into a CFD code. In this way, transient operation of PAR could be simulated without the need to model gas circulation outside the device. It was found that fi rst a slow downward fl ow of gas is developed, which may persist until the temperature of the catalyst foils rises. As soon as the gas inside the PAR absorbs enough heat to become lighter than the gas outside the PAR, it starts to fl ow upwards. Criteria for determining the start-up time of PAR were proposed. Model predictions were also compared with experimental data obtained in tests conducted at the THAI facility.
    Źródło:
    Nukleonika; 2018, 63, 2; 27-41
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Intensification of free-convection heat transfer in magnetically assisted bioreactor
    Autorzy:
    Konopacki, Maciej
    Kordas, Marian
    Rakoczy, Rafał
    Powiązania:
    https://bibliotekanauki.pl/articles/185473.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    natural convection
    rotating magnetic field
    magnetically assisted bioreactor
    Naturalna konwekcja
    wirujące pole magnetyczne
    bioreaktor wspomagany magnetycznie
    Opis:
    The effect of rotating magnetic field on the heat transfer process in a magnetically assisted bioreactor was studied experimentally. Experimental investigations are provided for the explanation of the influence of the rotating magnetic field on natural convection. The heat transfer coefficients and the Nusselt numbers were determined as a function of the product of Grashof and Prandtl dimensionless numbers. Moreover, the comparison of the thermal performance between the tested set-up and a vertical cylinder was carried out. The relative enhancement of heat transfer was characterized by the rate of the relative heat transfer intensification. The study showed that along with the intensity of the magnetic field the heat transfer increased.
    Źródło:
    Chemical and Process Engineering; 2019, 40, 3; 293--304
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermal analysis of a fully wet porous radial fin with natural convection and radiation using the spectral collocation method
    Autorzy:
    Khani, F.
    Darvishi, M. T.
    Gorla, R. S. R.
    Gireesha, B. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/264453.pdf
    Data publikacji:
    2016
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    porowatość
    naturalna konwekcja
    promieniowanie
    analiza termiczna
    wet porous radial fin
    natural convection
    radiation
    thermal analysis
    spectral collocation method
    Opis:
    Heat transfer with natural convection and radiation effect on a fully wet porous radial fin is considered. The radial velocity of the buoyancy driven flow at any radial location is obtained by applying Darcy’s law. The obtained non-dimensionalized ordinary differential equation involving three highly nonlinear terms is solved numerically with the spectral collocation method. In this approach, the dimensionless temperature is approximated by Chebyshev polynomials and discretized by Chebyshev-Gausse-Lobatto collocation points. A particular algorithm is used to reduce the nonlinearity of the conservation of energy equation. The present analysis characterizes the effect of ambient temperature in different ways and it provides a better picture regarding the effect of ambient temperature on the thermal performance of the fin. The profiles for temperature distributions and dimensionless base heat flow are obtained for different parameters which influence the heat transfer rate.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2016, 21, 2; 377-392
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Badanie procesu suszenia konwekcyjnego pietruszki korzeniowej
    Testing the convective-drying process of parsley root
    Autorzy:
    Skorupska, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/291036.pdf
    Data publikacji:
    2005
    Wydawca:
    Polskie Towarzystwo Inżynierii Rolniczej
    Tematy:
    suszenie
    konwekcja naturalna
    pietruszka korzeniowa
    drying
    natural convection
    root parsley
    Opis:
    Badano wpływ temperatury czynnika suszącego 50, 60 i 70°C i kształtu cząstek pietruszki korzeniowej na kinetykę procesu suszenia w warunkach konwekcji naturalnej. Doświadczalne krzywe suszenia i szybkości suszenia kinetyki suszenia pietruszki w cienkiej warstwie podzielono na dwa etapy, z których końcowy opisano modelem. Określono zakres zmian szybkości suszenia i średnią wartość szybkości suszenia w funkcji zawartości wody.
    An influence of the drying-medium temperature 50, 60, 70°C and the shape of the parsley-root particles on the kinetics of the drying process under the conditions of natural convection was investigated. Experimental curves of drying and drying rate kinetics of parsley in a thin layer were divided into two stages, where the final one was determined using a model. The scope of changes in drying and the average drying rate were determined as a function of water content.
    Źródło:
    Inżynieria Rolnicza; 2005, R. 9, nr 9, 9; 313-320
    1429-7264
    Pojawia się w:
    Inżynieria Rolnicza
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Charakterystyka suszarnicza owoców bzu czarnego
    Drying characteristics for elder fruits
    Autorzy:
    Peroń, S.
    Surma, M.
    Zdrojewski, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/290090.pdf
    Data publikacji:
    2010
    Wydawca:
    Polskie Towarzystwo Inżynierii Rolniczej
    Tematy:
    suszenie
    owoc
    bez czarny
    konwekcja naturalna
    drying
    elder
    fruit
    natural convection
    Opis:
    Badano wpływ temperatury suszenia na dynamikę narastania temperatury wnętrza owoców bzu czarnego, szybkość ich wysychania a także ich skurcz suszarniczy i zdolność do rehydracji. Suszenie prowadzono w warunkach konwekcji naturalnej w temperaturach 50, 60, 70°C przy początkowej wilgotności surowca około 75%. Wyniki przedstawiono w postaci wykresów oraz równań korelacyjnych.
    The research involved examination of drying temperature impact on the dynamics of temperature rise inside elder fruits, drying rate, and their drying shrinkage and ability to rehydration. Drying was carried out in natural convection conditions at temperatures: 50, 60, 70°C at initial material humidity.
    Źródło:
    Inżynieria Rolnicza; 2010, R. 14, nr 2, 2; 117-123
    1429-7264
    Pojawia się w:
    Inżynieria Rolnicza
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The natural convection inside a 3D triangular cross section cavity filled with nanofluid and included cylinder with different arrangements
    Autorzy:
    Ghoben, Zainab Kareem
    Hussein, Ahmed Kadhim
    Powiązania:
    https://bibliotekanauki.pl/articles/2096184.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    natural convection
    triangular cavity
    inner cylinder
    nanofluid
    3D
    konwekcja naturalna
    Opis:
    In this paper the laminar unsteady natural convection heat transfer of (Al2O3-water) nanofluid inside 3D triangular cross section cavity was investigated. The cavity was heated differentially, the vertical walls were kept at different constant temperatures. The left hot and the right cold. The effect of the solid volume fraction was examined for two values and compared with the pure water results. The (Ra) range studied was (103≤Ra≤106). Inserting cylindrical body inside the cavity also investigated in three cases. One concentric cylinder has radius (15%) of the cavity side length. The other cases were of two cylinders having radius (7.5%) of the cavity side length, aligned vertically or nonaligned. The results show that the higher solid volume fraction gives the maximum enhancement of the average (Nu) and this enhancement increases with (Ra) increase. For the cases with inner cylinders, the average (Nu) enhanced for the case of double cylinders over single cylinder. On other hand, the nonaligned position of the cylinders giving more enhancement than other position. As like as, the location of maximum horizontal or vertical velocities were varied with the cylinders position while (Ra) has no effect.
    Źródło:
    Diagnostyka; 2022, 23, 2; no. art. 2022205
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of aspect ratio of enclosure on free convection from horizontal cylinders in Bingham plastic fluids
    Autorzy:
    Baranwal, Ashok Kumar
    Gupta, Anoop Kumar
    Tiwari, Anurag Kumar
    Melnik, Roderick
    Powiązania:
    https://bibliotekanauki.pl/articles/2173430.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Bingham plastic fluids
    aspect ratio
    Rayleigh number
    Nusselt number
    natural convection
    płyn plastikowy Bingham
    współczynnik proporcji
    liczba Rayleigha
    liczba Nusselta
    naturalna konwekcja
    Opis:
    Heat transfer in steady free convection from differentially heated cylinders enclosed in a rectangular duct filled with Bingham plastic fluids has been solved numerically for the ranges of the dimensionless groups as, Rayleigh number, 102 Ra 106; Prandtl number, 10 Pr 100 and, Bingham number, 0 Bn 50 for aspect ratios AR = 05, 0.6, 0.7, 0.8, 0.9 and 2. The streamlines, isotherm contours, yield surfaces, local and average Nusselt numbers were analysed and discussed. It is found that as the aspect ratio of the enclosure increases from 0.5 to 0.9, the average Nusselt number on the surface of the hot cylinder increases as a larger amount of fluid takes part in convection. Moreover, at sufficiently large Bingham numbers, yield stress forces dominate over buoyancy causing the flow to cease and thus the Nusselt number approaches its conduction limit. Finally, the Nusselt number approaches its conduction limit once the maximum Bingham number is reached.
    Źródło:
    Chemical and Process Engineering; 2022, 43, 2; 271--277
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Charakterystyka suszarnicza owoców rokitnika pospolitego poddanych wstępnym zabiegom przygotowawczym
    Drying characteristic of common sea-buckthorn subjected to initial preparation treatments
    Autorzy:
    Peroń, S.
    Surma, M.
    Zdrojewski, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/288877.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Inżynierii Rolniczej
    Tematy:
    suszenie
    owoc
    rokitnik zwyczajny
    konwekcja naturalna
    drying
    common sea-buckthorn
    natural convection
    Opis:
    Celem pracy było zbadanie dynamiki wysychania owoców rokitnika w warunkach konwekcji naturalnej. Do badań użyto świeżych owoców rokitnika pospolitego o wilgotności ok. 79% - przygotowanych na 3 sposoby - to jest gniecionych, nakłuwanych oraz całych. Suszenie prowadzono w suszarce laboratoryjnej w nieruchomej warstwie przy jej wysokości 3cm i temperaturze 50°C. Wyniki przedstawiono w postaci wykresów oraz równań korelacyjnych.
    The purpose of the study was to investigate drying dynamics of the sea-buckthorn fruit in condition of natural convection. Fresh fruit of common sea-buckthorn of 79% moisture content were used for research. They were prepared in three forms- mashed, pricked and whole fruit. Drying process was carried out in a laboratory drier in a motionless layer at 3 cm height and temperature at 50°C. The results were presented in the form of schemes and correlation equations.
    Źródło:
    Inżynieria Rolnicza; 2011, R. 15, nr 9, 9; 169-176
    1429-7264
    Pojawia się w:
    Inżynieria Rolnicza
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    FEM simulation of triple diffusive natural convection along inclined plate in porous medium: prescribed surface heat, solute and nanoparticles flux
    Autorzy:
    Goyal, M.
    Goyal, R
    Bhargava, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/266289.pdf
    Data publikacji:
    2017
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    triple diffusive
    natural convection
    nanofluid
    binary base fluid
    porous medium
    solutal concentration flux
    nanoparticle concentration flux
    inclined plate
    naturalna konwekcja
    płyn bazowy
    nanocząstki
    Opis:
    In this paper, triple diffusive natural convection under Darcy flow over an inclined plate embedded in a porous medium saturated with a binary base fluid containing nanoparticles and two salts is studied. The model used for the nanofluid is the one which incorporates the effects of Brownian motion and thermophoresis. In addition, the thermal energy equations include regular diffusion and cross-diffusion terms. The vertical surface has the heat, mass and nanoparticle fluxes each prescribed as a power law function of the distance along the wall. The boundary layer equations are transformed into a set of ordinary differential equations with the help of group theory transformations. A wide range of parameter values are chosen to bring out the effect of buoyancy ratio, regular Lewis number and modified Dufour parameters of both salts and nanofluid parameters with varying angle of inclinations. The effects of parameters on the velocity, temperature, solutal and nanoparticles volume fraction profiles, as well as on the important parameters of heat and mass transfer, i.e., the reduced Nusselt, regular and nanofluid Sherwood numbers, are discussed. Such problems find application in extrusion of metals, polymers and ceramics, production of plastic films, insulation of wires and liquid packaging.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2017, 22, 4; 883--900
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Mechanistic Model of a Passive Autocatalytic Hydrogen Recombiner
    Autorzy:
    Rożeń, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/184900.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    hydrogen
    catalysis
    laminar flow
    natural convection
    forced convection
    wodór
    kataliza
    przepływ laminarny
    konwekcja naturalna
    konwekcja wymuszona
    Opis:
    A passive autocatalytic hydrogen recombiner (PAR) is a self-starting device, without operator action or external power input, installed in nuclear power plants to remove hydrogen from the containment building of a nuclear reactor. A new mechanistic model of PAR has been presented and validated by experimental data and results of Computational Fluid Dynamics (CFD) simulations. The model allows to quickly and accurately predict gas temperature and composition, catalyst temperature and hydrogen recombination rate. It is assumed in the model that an exothermic recombination reaction of hydrogen and oxygen proceeds at the catalyst surface only, while processes of heat and mass transport occur by assisted natural and forced convection in non-isothermal and laminar gas flow conditions in vertical channels between catalyst plates. The model accounts for heat radiation from a hot catalyst surface and has no adjustable parameters. It can be combined with an equation of chimney draft and become a useful engineering tool for selection and optimisation of catalytic recombiner geometry.
    Źródło:
    Chemical and Process Engineering; 2015, 36, 1; 3-19
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of the occurrence of natural convection in a bed of bars in vertical temperature gradient conditions
    Autorzy:
    Wyczółkowski, R.
    Musiał, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/239971.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    natural convection
    bed of bars
    porous material
    konwekcja naturalna
    złoża prętów
    materiały porowate
    Opis:
    The reason for undertaking this study was to determine the possible involvement of natural convection in the global heat transfer, that occurs in the heated steel rods bed. This problem is related to the setting of the effective thermal conductivity of the bars bed. This value is one of the boundary conditions for heating modeling of steel rods bundles during heat treatment. The aim of this study was to determine for which geometry of the bed bars, there will be no free convection. To analyze the problem the Rayleigh criterion was used. It was assumed that for the value of the number Ra < 1700 convection in the bed bars does not occur. For analysis, the results of measurements of the temperature distribution in the unidirectionally heated beds of bars were used. It has been shown, that for obtained, during the test, differences of temperature between the surfaces of adjacent rods, convection can occur only when the diameter of the rod exceeds 18 mm.
    Źródło:
    Archives of Thermodynamics; 2013, 34, 1; 71-83
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effects of pressure work over a semi-infinite vertical oscillating cylinder
    Autorzy:
    Sarojini, A.
    Palani, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1839892.pdf
    Data publikacji:
    2021
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    cylinder
    konwekcja naturalna
    metoda Cranka-Nicolsona
    finite difference
    pressure work
    oscillating
    skin friction
    Opis:
    An arithmetical methodology is used to study natural convection with properties of pressure work over a semi-infinite vertical oscillating cylinder. The governing partial differential equations are set up and the resulting equations are changed into a non-dimensional form using the proper non-dimensional quantities. The set of non-dimensional partial differential equations is solved arithmetically using a well-organized method known as the Crank-Nicolson method. The velocity, as well as temperature profiles for different values of parameters are studied with the assistance of graphs.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2021, 26, 1; 215-225
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Heat transfer by natural convection from a heated square inner cylinder to its elliptical outer enclosure utilizing nanofluids
    Autorzy:
    Bouras, Abdelkrim
    Taloub, Djedid
    Driss, Zied
    Debka, Siham
    Powiązania:
    https://bibliotekanauki.pl/articles/2174195.pdf
    Data publikacji:
    2022
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    konwekcja naturalna
    nanociecz
    ułamek objętościowy
    natural convection
    Rayleigh number
    nanofluid
    volume fraction
    square elliptical
    Opis:
    In this paper a numerical study of natural convection of stationary laminar heat transfers in a horizontal ring between a heated square inner cylinder and a cold elliptical outer cylinder is presented. A Cu-water nanofluid flows through this annular space. Different values of the Rayleigh number and volume fraction of nanoparticles are studied. The system of equations governing the problem was solved numerically by the fluent calculation code based on the finite volume method and on the Boussinesq approximation. The interior and exterior surfaces are kept at constant temperature. The study is carried out for Rayleigh numbers ranging from 310 to 510. We have studied the effects of different Rayleigh numbers and volume fraction of nanoparticles on natural convection. The results are presented as isotherms, isocurrents, and local and mean Nusselt numbers. The aim of this study is to study the influence of the thermal Rayleigh number and volume fraction of nanoparticles on the heat transfer rate.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2022, 27, 2; 22--34
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance of four different nanoparticles in boundary layer flow over a stretching sheet in porous medium driven by buoyancy force
    Autorzy:
    Ammani Kuttan, B.
    Manjunatha, S.
    Jayanthi, S.
    Gireesha, B. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/264960.pdf
    Data publikacji:
    2020
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    konwekcja naturalna
    nanociecze
    rozwiązania numeryczne
    natural convection
    porous parameter
    nanofluid
    numerical solutions
    volume fraction
    Opis:
    This contemporary work explores the theoretical analysis of energy transfer performance of distinct nanoparticles (silver, copper, aluminium oxide and titanium oxide) adjacent to a moving surface under the influence of a porous medium which is driven by the buoyancy force. A mathematical model is presented which is converted to similarity equations by employing similarity transformation. The condensed nonlinear equations were approximated by the iterative method called RKF 45th-order. The flow and energy transference characteristics are explained through graphs and tabulated values. The notable findings are: silver- water is an appropriate nanofluid for enhancing the thermal conductivity of the base fluid. Titanium oxide – water shows a lower fluid flow movement due to porosity.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2020, 25, 2; 1-10
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Układ pomiarowy do badań charakterystyk chłodzenia radiatorów z wykorzystaniem pomiarów termowizyjnych
    The measurement system for research on characteristic of cooling of radiators using infrared thermography
    Autorzy:
    Klecha, D.
    Minkina, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/267843.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
    Tematy:
    termografia
    termowizja
    radiatory
    konwekcja naturalna
    badania modelowe
    COMSOL Multiphysics®
    thermography
    thermovision
    radiators
    natural convection
    calculations
    Opis:
    W artykule przedstawiono metodę pozwalającą na porównanie jakości chłodzenia wybranych typów radiatorów w warunkach konwekcji swobodnej z wykorzystaniem pomiarów termowizyjnych oraz autorskiego stanowiska badawczego. W tym celu zbudowano układ pomiarowy, który może być użyty do generowania identycznych temperatur pod czterema polami grzewczymi w tym samym czasie i w tych samych warunkach wymiany ciepła. Na obszarze pól grzewczych umieszczono badane radiatory. Odczyty wartości temperatury z analogowych czujników temperatury i termogramów zostały użyte do porównania, który radiator ma najniższa temperaturę na początku i na końcu pomiarów. Wyniki badań eksperymentalnych porównano z wynikami badań modelowych z wykorzystaniem środowiska programistycznego COMSOL Multiphysics®. Pozycje literaturowe w małym stopniu opisują podobną problematykę. Na podstawie wyników uzyskanych z przeprowadzonych pomiarów i badań modelowych, sformułowano wnioski dotyczące jakości chłodzenia wybranych typów radiatorów.
    The aim of t his paper is to discuss method to compare cooling parameter in selected radiators. In this purpose measurement system was created which can be used to generate identical temperature under four radiators in the same time and conditions. Readings from analog sensors and thermograms were used to compare which radiator has the lowest temperature at the beginning and at the end of the measurement. Paper describes method to compare radiators using measurements from sensors and thermograms which is supplement to the theoretical calculations. Literature positions discuss this method slightly. Method is given capabilities to analyse whole process of cooling and deduce additional conclusions. Differences between temperatures of the radiators are noticeable and can be used to select the most performance radiator. The model research was compared with calculations form COMSOL Multiphysics®. The coolest radiator was different than this from experiment. This is the initial research. Next stage of the work will be carried out extensive research with the other radiators which will contain different shapes, weights and surface areas.
    Źródło:
    Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2017, 54; 117-121
    1425-5766
    2353-1290
    Pojawia się w:
    Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Rayleigh number on internal eccentricity in a heated horizontal elliptical cylinder to its coaxial square enclosure
    Autorzy:
    Bouras, Abdelkrim
    Taloub, Djedid
    Driss, Zied
    Powiązania:
    https://bibliotekanauki.pl/articles/1839785.pdf
    Data publikacji:
    2020
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    konwekcja naturalna
    płyn Newtona
    liczba Rayleigha
    natural convection
    newtonian fluid
    geometry ratio
    Rayleigh number
    elliptical cylinder
    Opis:
    This paper deals with numerical investigation of a natural convective flow in a horizontal annular space between a heated square inner cylinder and a cold elliptical outer cylinder with a Newtonian fluid. Uniform temperatures are imposed along walls of the enclosure. The governing equations of the problem were solved numerically by the commercial code Fluent, based on the finite volume method and the Boussinesq approximation. The effects of Geometry Ratio GR and Rayleigh numbers on fluid flow and heat transfer performance are investigated. The Rayleigh number is varied from 103 to 106. Throughout the study the relevant results are presented in terms of isotherms, and streamlines. From the results, we found that the increase in the Geometry Ratio B leads to an increase of the heat transfer coefficient. The heat transfer rate in the annulus is translated in terms of the average Nusselt numbers along the enclosure's sides. Tecplot 7 program was used to plot the curves which cleared these relations and isotherms and streamlines which illustrate the behavior of air through the channel and its variation with other parameters. The results for the streamlines, isotherms, local and average Nusselt numbers average Nusselt numbers are compared with previous works and show good agreement.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2020, 25, 3; 17-29
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Natural convection heat transfer in heated vertical tubes with internal rings
    Autorzy:
    Nayak, R. C.
    Roul, M. K.
    Sarangi, S. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/240303.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    heat flux
    heat transfer
    natural convection
    ring spacing
    ring thickness
    strumień cieplny
    wymiana ciepła
    konwekcja naturalna
    pierścień
    Opis:
    Experimental investigation of natural convection heat transfer in heated vertical tubes dissipating heat from the internal surface is presented. The test section is electrically heated and constant wall heat flux is maintained both circumferentially and axially. Four different test sections are taken having 45 mm internal diameter and 3.8 mm thickness. The length of the test sections are 450 mm, 550 mm, 700 mm and 850 mm. Ratios of length to diameter of the test sections are taken as 10, 12.22, 15.56, and 18.89. Wall heat fluxes are maintained at 250–3341 W/m2 . Experiments are also conducted on channels with internal rings of rectangular section placed at various distances. Thickness of the rings are taken as 4 mm, 6 mm, and 8 mm. The step size of the rings varies from 75 mm to 283.3 mm. The nondimensional ring spacing, expressed as the ratios of step size to diameter, are taken from 1.67 to 6.29 and the non-dimensional ring thickness, expressed as the ratios of ring thickness to diameter are taken from 0.089 to 0.178. The ratios of ring spacing to its thickness are taken as 9.375 to 70.82. The effects of various parameters such as length to diameter ratio, wall heat flux, ring thickness and ring spacing on local steady-state heat transfer behavior are observed. From the experimental data a correlation is developed for average Nusselt number and modified Rayleigh number. Another correlation is also developed for modified Rayleigh number and modified Reynolds number. These correlations can predict the data accurately within ±10% error.
    Źródło:
    Archives of Thermodynamics; 2018, 39, 4; 85--111
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    MHD natural convection flow with radiative heat transfer past an impulsively moving vertical plate with ramped temperature in the presence of hall current and thermal diffusion
    Autorzy:
    Seth, G. S.
    Mahato, G. K.
    Sarkar, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/955266.pdf
    Data publikacji:
    2013
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    konwekcja naturalna
    dyfuzja termiczna
    promieniowanie cieplne
    MHD natural convection
    Hall current
    ramped temperature
    thermal diffusion
    thermal radiation
    Opis:
    An investigation on an unsteady MHD natural convection flow with radiative heat transfer of a viscous, incompressible, electrically conducting and optically thick fluid past an impulsively moving vertical plate with ramped temperature in a porous medium in the presence of a Hall current and thermal diffusion is carried out. An exact solution of momentum and energy equations, under Boussinesq and Rosseland approximations, is obtained in a closed form by the Laplace transform technique for both ramped temperature and isothermal plates. Expressions for the skin friction and Nusselt number for both ramped temperature and isothermal plates are also derived. The numerical values of fluid velocity and fluid temperature are displayed graphically versus the boundary layer coordinate y for various values of pertinent flow parameters for both ramped temperature and isothermal plates. The numerical values of the skin friction due to primary and secondary flows are presented in tabular form for various values of pertinent flow parameters.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2013, 18, 4; 1201-1220
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Natural convection and radiation in a radial porous fin with variable thermal conductivity
    Autorzy:
    Darvishi, M. T.
    Kani, F.
    Gorla, R. S. R.
    Powiązania:
    https://bibliotekanauki.pl/articles/955178.pdf
    Data publikacji:
    2014
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    konwekcja naturalna
    promieniowanie
    wydajność cieplna
    metoda kolokacji
    porous radial fin
    natural convection
    radiation
    thermal performance
    spectral collocation method
    Opis:
    In this study, the effects of radiation and convection heat transfer in a radial porous fin are considered. The geometry considered is that of a rectangular profile fin. The porous fin allows the flow to infiltrate through it and solid-fluid interaction takes place. This study is performed using Darcy’s model to formulate the heat transfer equation. The thermal conductivity is assumed to be a function of temperature. The effects of the natural convection parameter Nc , radiation parameter Nr and thermal conductivity parameter m on the dimensionless temperature distribution and heat transfer rate are discussed. The results suggest that the radiation transfers more heat than a similar model without radiation.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2014, 19, 1; 27-37
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigations of Couette flow unsteady radiative convective heat transfer in a vertical channel using the generalized method of lines (MOL)
    Autorzy:
    Sowayan, Ahmed S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2174210.pdf
    Data publikacji:
    2022
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    promieniowanie
    konwekcja naturalna
    metoda Runge-Kutty
    vertical channel
    radiation
    natural convection
    method of lines (MOL)
    Runge-Kutta method
    Opis:
    This study describes a very efficient and fast numerical solution method for the non-steady free convection flow with radiation of a viscous fluid between two infinite vertical parallel walls. The method of lines (MOL) is used together with the Runge-Kutta ODE Matlab solver to investigate this problem numerically. The presence of radiation adds more stiffness and numerical complexity to the problem. A complete derivation in dimensionless form of the governing equations for momentum and energy is also included. A constant heat flux condition is applied at the left wall and a transient numerical solution is obtained for different values of the radiation parameter (R). The results are presented for dimensionless velocity, dimensionless temperature and Nusselt number for different values of the Prandtl number (Pr), Grashof number (Gr), and the radiation parameter (R). As expected, the results show that the convection heat transfer is high when the Nusselt number is high and the radiation parameter is low. It is also shown that the solution method used is simple and efficient and could be easily adopted to solve more complex problems.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2022, 27, 3; 199--211
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Unsteady/steady natural convection flow of reactive viscous fluid in a vertical annulus
    Autorzy:
    Jha, B. K.
    Samaila, A. K.
    Ajibade, A. O.
    Powiązania:
    https://bibliotekanauki.pl/articles/265663.pdf
    Data publikacji:
    2013
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    konwekcja naturalna
    lepki płyn
    egzotermiczna otulina
    unsteady/steady natural convection flow
    reactive viscous fluid
    exothermic
    open ended vertical annulus
    Opis:
    This paper presents both analytical and numerical analyses of a fully developed unsteady/steady natural convection flow of a reactive viscous fluid in an open ended vertical annulus. Analytical expressions for velocity, temperature, skin-friction and rate of heat transfer are obtained after simplifying and solving the governing differential equations with reasonable approximations. The interesting result found in this study is that an increase in non-dimensional time (t) , increases both temperature and velocity profiles until a steady-state value is attained. Subsequent results obtained by numerical calculations show excellent agreement with analytical results.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2013, 18, 1; 73-83
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical study on the effects of multiple internal diathermal obstructions on natural convection in a fluid-saturated porous enclosure
    Autorzy:
    Chordiya, J. S.
    Sharma, R. V.
    Powiązania:
    https://bibliotekanauki.pl/articles/139520.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    thermal insulation
    natural convection
    internal obstructions
    porous enclosure
    Darcy's law
    izolacja termiczna
    konwekcja naturalna
    przeszkody wewnętrzne
    obudowa porowata
    prawo Darcy'ego
    Opis:
    The present work aims at studying the effects of orientation, size, position, and the combination of multiple internal diathermal obstructions in a fluid-saturated square porous enclosure, generally encountered in thermal insulations. The overall objective is to suppress the natural convection fluid flow and heat transfer across a differentially heated porous enclosure. To serve this purpose, multiple diathermal obstructions are employed to mechanically protrude into a porous medium. It is sought to estimate the effect of various types of orientation, clustering and alternate positioning of obstructions by considering number of obstructions (Np), length of obstructions (λ), modified Rayleigh number (Ra*) on local and average Nusselt number (Nu). The Darcy model for porous media is solved using Finite difference method along with Successive Accelerated Replacement scheme. One of the findings is that the value of the Nusselt number decreases by increasing both, the number of obstructions as well as the length of obstructions irrespective of its orientation and positioning. The reduction in Nusselt number is significant with obstructions attached on lower half of the hot wall and/or on upper half of cold wall. In addition, the overall reduction in Nusselt number is slightly greater with obstructions attached explicitly to the cold wall.
    Źródło:
    Archive of Mechanical Engineering; 2018, LXV, 4; 553-578
    0004-0738
    Pojawia się w:
    Archive of Mechanical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Natural convection in a hydrodynamically and thermally anisotropic non-rectangular porous cavity: effect of internal heat generation/absorption
    Autorzy:
    Chandran, P.
    Sacheti, N. C.
    Bhadauria, B. S.
    Singh, A. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/264468.pdf
    Data publikacji:
    2018
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    konwekcja naturalna
    materiały porowate
    przepuszczalność
    dyfuzyjność cieplna
    źródło ciepła
    natural convection
    trapezoidal cavity
    porous medium
    permeability
    thermal diffusivity
    Darcy's law
    heat source/sink
    Opis:
    Laminar natural convection in a trapezoidal porous vertical cavity has been investigated in this work. It is assumed that the porous enclosure is filled up with a permeable material subject to hydrodynamic and thermal anisotropy, the flow being governed by the Darcy law as applicable to a non-isotropic medium. It is further assumed that (i) there is heating at the left vertical wall and cooling at the right wall of the enclosure and (ii) the flow domain is subject to the presence of heat source or heat sink. The partial differential equations governing the resulting free convection have been solved numerically in the non-dimensional forms. There arises a number of parameters relating to buoyancy, internal heating, cavity aspect ratio and inclination of the upper surface to the horizontal. The influence of these parameters has been illustrated and analyzed through contours of streamlines and isotherms. We have also discussed the role of internal heating as well as anisotropy on the heat transfer characteristics.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2018, 23, 3; 595-609
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An algorithm of velocity field evaluation via temperature field measurement on the basic of streamline-defined coordinates
    Autorzy:
    Leble, S.
    Shaban, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1940181.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Gdańska
    Tematy:
    free convective heat transfer
    isothermal surface
    numerical analysis
    natural convection
    streamline coordinate system
    ciepło konwekcyjne
    przepływ ciepła
    powierzchnia izotermiczna
    analiza numeryczna
    konwekcja naturalna
    transformacja współrzędnych
    Opis:
    A new algorithm is presented for evaluating the velocity field of the heat convection flow from a vertical solid flat plate using the temperature field. Using the coordinate transformation of Cartesian coordinates, to coordinates defined via streamlines, and visible in such coordinate approximations, it is possible to express the basic flow fields in terms of the temperature gradients only. After discretization we formulate approximated sufficient finite-difference formulas to evaluate the velocity field using the experimental data.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2017, 21, 3; 247-259
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect Of Natural Convection On Directional Solidification Of Pure Metal
    Wpływ konwekcji swobodnej na krzepnięcie kierunkowe czystego metalu
    Autorzy:
    Skrzypczak, T.
    Węgrzyn-Skrzypczak, E.
    Winczek, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/356653.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    pure metal
    solidification
    sharp interface
    natural convection
    Finite Element Method (FEM)
    Level Set Method
    czysty metal
    krzepnięcie
    ostry front
    konwekcja naturalna
    metoda elementów skończonych
    metoda poziomic
    Opis:
    The paper is focused on the modeling of the directional solidification process of pure metal. During the process the solidification front is sharp in the shape of the surface separating liquid from solid in three dimensional space or a curve in 2D. The position and shape of the solid-liquid interface change according to time. The local velocity of the interface depends on the values of heat fluxes on the solid and liquid sides. Sharp interface solidification belongs to the phase transition problems which occur due to temperature changes, pressure, etc. Transition from one state to another is discontinuous from the mathematical point of view. Such process can be identified during water freezing, evaporation, melting and solidification of metals and alloys, etc. The influence of natural convection on the temperature distribution and the solid-liquid interface motion during solidification of pure copper is studied. The mathematical model of the process is based on the differential equations of heat transfer with convection, Navier-Stokes equation and the motion of the interface. This system of equations is supplemented by the appropriate initial and boundary conditions. In addition the continuity conditions at the solidification interface must be properly formulated. The solution involves the determination of the temporary temperature and velocity fields and the position of the interface. Typically, it is impossible to obtain the exact solution of such problem. The numerical model of solidification of pure copper in a closed cavity is presented, the influence of the natural convection on the phase change is investigated. Mathematical formulation of the problem is based on the Stefan problem with moving internal boundaries. The equations are spatially discretized with the use of fixed grid by means of the Finite Element Method (FEM). Front advancing technique uses the Level Set Method (LSM). Chorin’s projection method is used to solve Navier-Stokes equation. Such approach makes possible to uncouple velocities and pressure. The Petrov-Galerkin formulation is employed to stabilize numerical solutions of the equations. The results of numerical simulations in the 2D region are discussed and compared to the results obtained from the simulation where movement of the liquid phase was neglected.
    Praca porusza problematykę modelowania kierunkowego krzepnięcia czystego metalu. Podczas tego procesu obserwuje się formowanie ostrego frontu krzepnięcia w postaci powierzchni separującej ciecz i ciało stałe w przypadku trójwymiarowym lub krzywej w przypadku płaskim. Położenie oraz kształt interfejsu krzepnięcia zmieniają się w czasie a wartości prędkości lokalnych zależą od różnicy intensywności strumieni ciepła po stronie ciała stałego i cieczy. Krzepnięcie z ostrym frontem należy do grupy procesów z przemianami fazowymi, które warunkowane są zmianami temperatury, ciśnienia, itp. Przejście fazowe z jednego stanu w drugi ma z matematycznego punktu widzenia charakter nieciągły. Procesy tego typu można zidentyfikować podczas zamarzania wody, parowania, topnienia i krzepnięcia metali i stopów, itp. W pracy zbadano wpływ zjawiska konwekcji swobodnej na chwilowy rozkład temperatury oraz ruch granicy narastania fazy stałej podczas krzepnięcia czystej miedzi w obszarze płaskim. Model matematyczny sformułowano na bazie równań różniczkowych transportu ciepła z konwekcją, Naviera-Stokesa i ruchu frontu krzepnięcia. Układ równań uzupełniono odpowiednimi warunkami początkowymi i brzegowymi oraz warunkami ciągłości na froncie. Rozwiązanie obejmuje chwilowe rozkłady temperatury, prędkości oraz położenie granicy międzyfazowej. Sformułowanie matematyczne zagadnienia bazuje na modelu z ruchomymi granicami wewnętrznymi, czyli tzw. modelu Stefana. Równania zostały zdyskretyzowane przestrzennie z wykorzystaniem metody elementów skończonych. W modelu numerycznym wykorzystano siatkę niezmienną w czasie. Do propagacji frontu użyto metody poziomic. Do wyznaczenia prędkości w cieczy wykorzystano metodę rzutowania, która poprzez eliminację ciśnienia z równania pędu pozwala na rozprzężenie prędkości i ciśnień. Równania rozwiązano z wykorzystaniem sformułowania Petrova-Galerkina. Omówiono wyniki analizy numerycznej oraz porównano je z wynikami otrzymanymi z symulacji, w której pominięto ruch cieczy.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2A; 835-841
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Heat transfer analysis of non-Newtonian natural convective fluid flow using Homotopy Perturbation and Daftardar-Gejiji & Jafari Methods
    Autorzy:
    Adeleye, Olurotimi
    Yinusa, Ahmed
    Powiązania:
    https://bibliotekanauki.pl/articles/122431.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
    Tematy:
    non-Newtonian fluid
    natural convection
    vertically infinite plates
    Daftardar-Gejiji & Jafari Method
    DJM
    Homotopy Perturbation Method
    HPM
    ciecz nieniutonowska
    konwekcja naturalna
    metoda Daftardar-Gejiji i Jafari
    metoda perturbacji homotopii
    Opis:
    In this paper, the analytical solution of natural convective heat transfer of a non-Newtonian fluid flow between two vertical infinite plates using the Homotopy Perturbation Method (HPM) and Daftardar-Gejiji & Jafari Method (DJM) is presented. The heat transfer problem of natural convection is observed in many engineering fields including geothermal systems, heat exchangers, petroleum reservoirs, nuclear waste reserves, etc. The problem which is modelled as fully coupled nonlinear ordinary differential equations requires special analytical techniques for its solution. The solutions are obtained using an exact analytical method: the Homotopy Perturbation Method (HPM) and a semi-analytical method: the Daftardar-Gejiji & Jafari Method (DJM). These solutions are compared with solutions obtained from the Runge-Kutta numerical method. The results are in good agreement with the numerical solutions. The effects of the Eckert number, Prandtl number and the non-Newtonian fluid viscosity parameter on the non-dimensional temperature and velocity of the fluid are investigated. The results obtained from the analytical method show that the method can be applied to predict excellent results of the problem and can be used for parametric studies of the problem. From the results, it is shown that when the Prandtl number and the Eckert number are increased, there is an increase in both temperature and fluid flow velocity.
    Źródło:
    Journal of Applied Mathematics and Computational Mechanics; 2019, 18, 2; 5-18
    2299-9965
    Pojawia się w:
    Journal of Applied Mathematics and Computational Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Magnetoconvection of nanofluid in a partially heated cavity with isothermal blockage
    Autorzy:
    Nagaraj, Suresh
    Nagarajan, Nithyadevi
    Powiązania:
    https://bibliotekanauki.pl/articles/2175528.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
    Tematy:
    Al2O3 nanofluid
    finite volume method
    inclined magnetic field
    isothermal square body
    natural convection
    partial bottom heating
    nanopłyn Al2O3
    metoda objętości skończonych
    nachylone pole magnetyczne
    konwekcja naturalna
    Opis:
    Natural convection characteristics of Al2O3-water nanofluid in a cavity is investigated numerically under the influence of a inclined magnetic field. The bottom wall is partially heated, and the top wall is cooled and the remaining regions of the cavity are kept adiabatic. An isothermally heated square blockage of the different rectangular size is placed at the centre of the cavity. The schematic model is converted into mathematical form, and the non-dimensional equations are discretized by the finite volume method using power law scheme and solved by Semi-Implicit Method for Pressure Linked Equation algorithm. The relevant parameters such as Rayleigh number (104-106), Hartmann numer (10-500), size of blockage ratio (0.25-0.75), length of the heat source (0.25-1.0) and inclination angle of the magnetic field (0°-90° on the flow and temperature fields are examined. Results are presented in terms of streamlines, isotherms, velocity profile, local and average Nusselt number. It was found that for low Hartmann numbers, the average heat transfer rate attained the maximum at the inclined magnetic field of γ = 45°. In addition, the blockage ratio of B = 0.75 enhanced the higher heat transfer rate for all values of γ.
    Źródło:
    Journal of Applied Mathematics and Computational Mechanics; 2022, 21, 2; 77--90
    2299-9965
    Pojawia się w:
    Journal of Applied Mathematics and Computational Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-28 z 28

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