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Wyszukujesz frazę "turbulence kinetic energy" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Effect of D-shaped, reverse D-shaped and U-shaped turbulators in solar air heater on thermo-hydraulic performance
Autorzy:
Ghildyal, Abhishek
Bisht, Vijay Singh
Bhandari, Prabhakar
Rawat, Kamal Singh
Powiązania:
https://bibliotekanauki.pl/articles/27312225.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
CFD
renewable energy
solar air heater
turbulence kinetic energy
thermo-hydraulic performance
Opis:
As the cost of fuel rises, designing efficient solar air heaters (SAH) becomes increasingly important. By artificially roughening the absorber plate, solar air heaters’ performance can be augmented. Turbulators in different forms like ribs, delta winglets, vortex generators, etc. have been introduced to create local wall turbulence or for vortex generation. In the present work, a numerical investigation on a solar air heater has been conducted to examine the effect of three distinct turbulators (namely D-shaped, reverse D- and U-shaped) on the SAH thermo-hydraulic performance. The simulation has been carried out using the computational fluid dynamics, an advanced and modern simulation technique for Reynolds numbers ranging from 4000 to 18000 (turbulent airflow). For the purpose of comparison, constant ratios of turbulator height/hydraulic diameter and pitch/turbulator height, of 0.021 and 14.28, respectively, were adopted for all SAH configurations. Furthermore, the fluid flow has also been analyzed using turbulence kinetic energy and velocity contours. It was observed that the U-shaped turbulator has the highest value of Nusselt number followed by D-shaped and reverse D-shaped turbulators. However, in terms of friction factor, the D-shaped configuration has the highest value followed by reverse D-shaped and U-shaped geometries. It can be concluded that among all SAH configurations considered, the U-shaped has outperformed in terms of thermohydraulic performance factor.
Źródło:
Archives of Thermodynamics; 2023, 44, 2; 3--20
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of 3D flow in VKI-Genoa turbine cascade including laminar-turbulent transition
Autorzy:
Yerschov, S.
Derevyanko, A.
Yakovlev, V.
Gryzun, M.
Powiązania:
https://bibliotekanauki.pl/articles/1938601.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska
Tematy:
numerical simulation
3D flow
turbine cascade
laminar-turbulent transition
turbulence kinetic energy
secondary flows
losses
Opis:
This study presents a numerical simulation of a 3D viscous flow in the VKI-Genoa cascade taking into account the laminar-turbulent transition. The numerical simulation is performed using the Reynolds-averaged Navier-Stokes equations and the two-equation k-ω SST turbulence model. The algebraic Production Term Modification model is used for modeling the laminar-turbulent transition. Computations of both fully turbulent and transitional flows are carried out. The Mach number contours, the turbulence kinetic energy, the entropy function as well as the limiting streamlines are presented. Our numerical results demonstrate the influence of the laminar-turbulent transition on the secondary flow pattern. The comparison between the present computational results and the existing experimental and numerical data shows that the proposed approach reflects sufficiently the physics of the laminar-turbulent transition in turbine cascades.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2016, 20, 1; 43-61
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the prediction of flow patterns and losses in HP axial turbine stages using 3D RANS solver with two turbulence models
Autorzy:
Lampart, P.
Świrdyczuk, J.
Gardzielewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/1955806.pdf
Data publikacji:
2001
Wydawca:
Politechnika Gdańska
Tematy:
high-pressureaxial turbine
RANS solver
RANS equations
turbulence modelling
kinetic energy losses
Opis:
An experimentally tested air turbine stage and a real high-pressure (HP) steam turbine stage are calculated using the 3D RANS solver FlowER supplemented with the Baldwin-Lomax and Menter shear stress transport (SST) models. The computations of the model air turbine stage show that the Menter SST model gives better agreement with the experimental data as far as the span-wise distribution of exit velocities and swirl angle. The comparison of performance of the two turbulence models exhibits differences in predicting flow patterns and losses in the considered HP turbine stage. The main differences concern the development of secondary flows and separations. There is a significant span-wise redistribution of losses between these two models. The tendency is that for the same relatively refined grid resolutions, the level of pitch/span averaged losses for the Menter SST turbulence model is slightly above that of Baldwin-Lomax.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2001, 5, 2; 191-206
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Modeling of Compound Channels for Determining Kinetic Energy and Momentum Correction Coefficients Using the OpenFOAM Software
Autorzy:
Mehranfar, Nariman
Ghanbari-Adivi, Elham
Powiązania:
https://bibliotekanauki.pl/articles/2097752.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
compound channel
floodplain
OpenFOAM
SST turbulence models
correction coefficient
kinetic energy
momentum
Opis:
The non-uniformity of the flow velocity distribution in each section of compound channels and in the main channel-floodplain interface area causes errors in estimating water surface profile, flood routing, pollution transfer, and so on. To reduce the impacts of non-uniformity on the exact calculation of kinetic energy and momentum, α and β correction coefficients are used, respectively. However, the determination method of these coefficients is a challenging issue in river engineering. This study used the OpenFOAM Software to determine these coefficients numerically for two laboratory models of compound open channels of which the data are available, using the single-phase pimpleFoam solver to do modeling in the mentioned software and the k-ωSST turbulence model to calculate the flow characteristics. Based on the results, the highest difference (13%) between the results estimated by the software and those obtained from the lab experiments was seen in the low flow depth where the flow left the main channel and entered the floodplain of a very shallow depth, possibly due to the grid generation of this area. This difference decreased as the flow depth increased, and its average was 6.65% for α coefficient and 2.32% for β coefficient in all cases, which means the results of numerical modeling and the experimental data conformed well, and the OpenFOAM software can be successfully used in flow modeling and analyzing flow characteristics in compound channels.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2022, 69, 1; 27-43
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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