Natural Convection
Mostrando 13-24 de 59 artigos, teses e dissertações.
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13. Magnetic effect on free convection in a non-darcy porous medium saturated with doubly stratified power-law fluid
Natural convection heat and mass transfer along a vertical plate embedded in a doubly stratified power-law fluid saturated non-Darcy porous medium with uniform heat and mass flux is presented. The governing partial differential equations are transformed into ordinary differential equations using similarity transformations and then solved numerically. The eff
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2011-03
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14. Sistema de captaÃÃo de energia solar para uma torre de dessalinizaÃÃo tÃrmica com recuperaÃÃo de calor / System of captation of solar energy for a tower of thermal dessalinizaÃÃo with heat recovery
This dissertation presents the experimental result of a system to absorb solar energy to heat up a desalination tower with heat recovery mechanism and a change made in the heated water distribution at the heat storage tank. The system to absorb solar energy consists of solar thermal flat plate collectors for high temperatures and it responsible for the conve
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/09/2009
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15. Turbulent natural convection in enclosures using large-eddy simulation with localized heating from horizontal bottom surface and cooling from vertical surfaces
Turbulent natural convection of air that happens into inner square cavity with localized heating from horizontal bottom surface has been numerically investigated. Localized heating is simulated by a centrally located heat source on the bottom wall, and two values of the dimensionless heat source length ? are considered in the present work. Solutions are obta
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2009-09
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16. Simplified engine/nacelle heat transfer case analysis via CFD modeling for supporting the preliminary design of nacelle cooling/ventilation system.
An aeronautical engine is a complex machine composed of different components operating at different temperatures that in conjunction with the nacelle creates a crowded region with the coupled heat transfer mechanisms to be covered by the nacelle cooling/ventilation system. The final configuration of this system is defined through a demanding refinement of th
Publicado em: 2009
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17. Um estudo numérico sobre a transferência de calor na camada limite turbulenta
The present work is a numerical study on the applicaion of analogies between heat and momentum difusion as a methodology to impose heat flux boundary conditions in turbulent boundary layer flows. In order to validate the proposed methodology the following cases were tested: a) a study of turbulent flows over slightly heated flat plates and with unheated star
Publicado em: 2009
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18. Estudo comparativo entre teoria construtal e entrânsia para casos de resfriamento de fontes de calor em cavidade / Comparactive study between constructal theory end the entransy treory for the cooling cases of heat sources in a cavity
In the present work the cooling was treated by natural convection of one, three and five sources localized in a vertical wall of a rectangular cavity. One has approximated numerically the temperature field in the stationary state at different positions for each case. The conductivity and the dissipation of entransy were evaluated in all these cases and their
Publicado em: 2009
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19. Estruturas de aço sem revestimento contra fogo externas a edifícios em incêndio. / External unprotected steel structures in fire situation.
Steelworks outside a building in fire situation are exposed to radiation that come from the windows in the façade and from flames, as well as the convection of hot gases. The absorption of the heat for the element depends on its placement in relation to the openings. Margaret Law, based on many experimental data about fire in buildings, estimated the extern
Publicado em: 2009
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20. Natural convection heat transfer in partially open enclosures containing an internal local heat source
A numerical study was conducted to investigate steady heat transfer and flow phenomena of natural convection of air in enclosures, with three aspect ratios (H/W = 1, 2, and 4), within which there is a local heat source on the bottom wall at three different positions, Wh. This heat source occupies 1% of the total volume of the enclosure. The vertical walls in
Brazilian Journal of Chemical Engineering. Publicado em: 2007-09
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21. Power calibration of the TRIGA mark I nuclear research reactor
This paper presents the results and methodology used to calibrate the thermal power of the TRIGA Mark I IPR-R1 Research Reactor at the Nuclear Technology Development Centre (CDTN), in Belo Horizonte, Brazil. The TRIGA Mark I is a pool type reactor, cooled by water natural convection. The method used in the calibration consisted in the steady-state energy bal
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2007-09
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22. SIMULAÇÃO DA ETAPA DE RESFRIAMENTO DA POLIAMIDA NO PROCESSO DE MOLDAGEM ROTACIONAL / COOLING STAGE SIMULATION OF POLYAMIDE IN ROTATIONAL MOLDING PROCESS
In rotomolding, cooling stage is of fundamental importance to optimize the process in terms of productivity and quality of rotomolded parts. Therefore, the present work has concentrated in the study of this process stage through computational simulation via the multi-purpose commercial software ANSYSTM . It uses finite element method being widely used in eng
Publicado em: 2007
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23. Simulação do escoamento miscível decorrente da injeção de ácido em um meio poroso com dissolução parcial do meio / Flow simulation of the acid injection in porous media with partial dissolution of the porous media
Formulamos um modelo simplificado para o estudo do processo de injeção de solvente em reservatórios de petróleo, onde o fluido injetado (um ácido) tem a capacidade de dissolver parcialmente a matriz sólida. Como hipóteses principais, consideramos que o solvente e o soluto (componente químico que constitui o meio poroso) são espécies totalmente misc
Publicado em: 2007
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24. A K − W turbulence model for near-wall thermal flows / Um modelo k − w para escoamentos turbulentos parietais dilatáveis
The main goal of this work is to extend the K − W turbulence model proposed by Bredberg (2002), originally developed in order to simulate turbulent isothermal flows in which adverse pressure gradients occur, to simulate the effects of density variations exclusively due to the presence of thermal gradients - cases vastly applied in industry - implementi
Publicado em: 2006