Natural convection in a differentially heated square cavity with a horizontal partition plate on the hot wall
01 Dec 1993-Computer Methods in Applied Mechanics and Engineering (North-Holland)-Vol. 110, pp 143-156
About: This article is published in Computer Methods in Applied Mechanics and Engineering.The article was published on 1993-12-01. It has received 107 citations till now. The article focuses on the topics: Natural convection & Partition (politics).
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TL;DR: In this paper, a finite volume-based computational study of steady laminar natural convection (using Boussinesq approximation) within a differentially heated square cavity due to the presence of a single thin fin is presented.
Abstract: A finite-volume-based computational study of steady laminar natural convection (using Boussinesq approximation) within a differentially heated square cavity due to the presence of a single thin fin is presented. Attachment of highly conductive thin fins with lengths equal to 20, 35 and 50 percent of the side, positioned at 7 locations on the hot left wall were examined for Ra=10 4 , 10 5 , 10 6 , and 10 7 and Pr=0.707 (total of 84 cases). Placing a fin on the hot left wall generally alters the clockwise rotating vortex that is established due to buoyancy-induced convection. Two competing mechanisms that are responsible for flow and thermal modifications are identified. One is due to the blockage effect of the fin, whereas the other is due to extra heating of the fluid that is accommodated by the fin. The degree of flow modification due to blockage is enhanced by increasing the length of the fin. Under certain conditions, smaller vortices are formed between the fin and the top insulated wall
208 citations
TL;DR: In this paper, a numerical study has been carried out in differentially heated square cavities, which are formed by horizontal adiabatic walls and vertical isothermal walls, where a thin fin is attached on the active wall.
203 citations
142 citations
TL;DR: In this article, the authors focused on the numerical study of steady, laminar, conjugate natural convection in a square enclosure with an inclined thin fin of arbitrary length.
126 citations
TL;DR: In this article, the authors presented a numerical study of natural convection heat transfer and entropy generation of water-alumina nanofluid in baffled L-shaped cavity, where the left vertical and bottom walls were placed in hot and constant Th temperature and the middle horizontal and right vertical walls were in cold and constant Tc temperature.
114 citations
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TL;DR: In this paper, the authors used mesh refnement and extrapolation to obtain an accurate solution of the equations describing two-dimensional natural convection in a square cavity with differentially heated side walls.
Abstract: Details are given of the computational method used to obtain an accurate solution of the equations describing two-dimensional natural convection in a square cavity with differentially heated side walls. Second-order, central difference approximations were used. Mesh refnement and extrapolation led to solutions for 103⩽Ra⩽10 6 which are believed to be accurate to better than 1 per cent at the highest Rayleigh number and down to one-tenth of that at the lowest value.
2,529 citations
TL;DR: In this article, a number of contributed solutions to the problem of laminar natural convection in a square cavity have been compared with what is regarded as a solution of high accuracy, and the purposes of this exercise have been to confirm the accuracy of the bench mark solution and to provide a basis for the assessment of the various methods and computer codes used to obtain the contributed solutions.
Abstract: A number of contributed solutions to the problem of laminar natural convection in a square cavity have been compared with what is regarded as a solution of high accuracy. The purposes of this exercise have been to confirm the accuracy of the bench mark solution and to provide a basis for the assessment of the various methods and computer codes used to obtain the contributed solutions.
678 citations
TL;DR: In this article, the complex nature of the natural convection phenomena in enclosures is discussed and the boundary value problem is formulated, assuming that the motion is two-dimensional and steady, the fluid is incompressible and frictional heating is negligible.
Abstract: Publisher Summary This chapter discusses the complex nature of the natural convection phenomena in enclosures. It discusses the two basic configurations of natural convection— that is, a rectangular cavity and a horizontal circular cylinder. In rectangular cavities, consideration is given to the two-dimensional convective motion generated by the buoyancy force on the fluid in a rectangle and to the associated heat transfer. The two long sides are vertical boundaries held at different temperatures and the short sides can either be heat conducting or insulated. Particular attention is given to the different flow regimes that can occur and the heat transfer across the fluid space between the two plane parallel vertical boundaries. Although heat transfer by radiation may not be negligible it is independent of the other types of heat transfer and can be fairly accurately calculated separately. To formulate the boundary value problem that describes this phenomena it is assumed that: (a) the motion is two-dimensional and steady, (b) the fluid is incompressible and frictional heating is negligible, and (c) the difference between the hot wall and cold wall temperatures is small relative to the absolute temperatures of the cold wall. In horizontal circular cylinder, consideration is given to the large Rayleigh number flow with the Prandtl number large and the Grashof number of unit order of the magnitude.
382 citations
TL;DR: In this article, a Mach-Zehnder interferometer was used to investigate the convective heat transfer in a two-dimensional, partitioned enclosure of aspect ratio 1.
Abstract: Natural convection heat transfer within a two-dimensional, partitioned enclosure of aspect ratio 1 was investigated experimentally using a Mach-Zehnder interferometer. The vertical walls were maintained isothermal at different temperatures, while the horizontal walls and the partitions were insulated. Local and average heat-transfer coefficients were determined for the air and carbon dioxide filled enclosures both with and without partitions for Grashof numbers between 1.7×105 and 3.0×106 . Good agreement was found between the results in the present study for the nonpartitioned enclosure and those previously published. The partitions were found to significantly influence the convective heat transfer. Observations of the interferometric fringes indicated that the core region is unsteady, with the unsteadiness occasionally affecting the flow along the vertical isothermal walls, beginning at Grashof numbers as low as 5×105 .
149 citations
TL;DR: In this article, the effect of the partitions on the heat transfer across the enclosure is also studied and correlations for the Nusselt number as a function of RaL and partition length are generated for both conducting and nonconducting partition materials.
Abstract: / Heat transfer by natural convection in a two-dimensional rectangular enclosure fitted with partial vertical divisions is investigated experimentally. The horizontal walls of the enclosure are adiabatic while the vertical walls are maintained at different temperatures. The experiments are carrir8 out with water, n 3.5, for Rayleigh numbers in the range, 2.3 X 10 < RaL < 1.1 x 10 , and an aspect ratio, A = H/L = 1/2. The effect of the partial-vertical divisions on the fluid flow and temperature fields is investigated by dye-injection flow visualization and by thermocouple probes, respectively. The effect of the partitions on the heat transfer across the enclosure is also studied and correlations for the Nusselt number as a function of RaL and partition length are generated for both conducting and non-conducting partition materials. Partial divisions are found to have a significant effect on the heat transfer, especially when the divisions are adiabatic. The results also indicate that the partial divisions may have a stabilizing effect on the laminar-transitional flow on the heated vertical walls of the enclosure.
137 citations