Natural convection in a cavity with fins attached to both vertical walls

Abstract

Numerical calculations are presented for two-dimensional natural convection flow inside an air-filled cavity with fins/baffles-of length 0.1, 0.3, and 0.5 of the cavity width-attached along both the heated and the cooled side of the cavity. The governing equations in the stream function-vorticity formulation are solved using finite differences. The Arakawa differencing scheme is used to represent the convection terms. Flow characteristics are investigated for three baffle lengths and Grashof numbers in the range of 9.0 x 10 3 to 1.0 x 10 5 . A multicellular flow structure is found to exist for a baffle length of 0.1. However, when the baffle length is equal to 0.3 or greater, the fluid flow breaks down into secondary circulations-in addition to the primary circulationand that, in turn, results in higher heat transfer rates across the two sides of the cavity. NomenclatureGr = Grashof number, g/3ATw 3 /v 2 h = baffle length N = number of baffles Pr = Prandtl number, via T = temperature u' = nondimensional velocity in £ direction v' = nondimensional velocity in £ direction w = cavity width z = cavity length a = thermal diffusivity j8 = coefficient of thermal expansion d = baffle thickness £ = nondimensional spatial coordinate 0 = nondimensional temperature A = cavity aspect ratio, z/w v = kinematic viscosity £ = nondimensional spatial coordinate r = nondimensional timê = nondimensional stream function i// = stream function H = nondimensional vorticity co = vorticity

On the thermal performance of an internally finned three-dimensional cubic enclosure in natural convection

“…In spite of the constant pressure for more efficient heat transfer devices based on known techniques such as natural convection inside a cavity, very few papers deal with optimization of thermal performance [3,8,9]. Most of the bodywork found is of descriptive nature [10,11], in none of them heat transfer augmentation under global constraints was the main concern. This motivates the present study to further investigate theoretically and numerically the behavior of a class of improved enclosures.…”

Laminar natural convection heat transfer in a differentially heated cavity with a thin porous fin attached to the hot wall

“…Heat transfer enhancement in cavities due to incorporation of obstacles and fins attached to the walls has also received significant consideration in recent years [6][7][8][9][10]. Oosthuizen and Paul [11] studied numerically an air-filled rectangular cavity with a horizontal plate on the cold wall.…”

Heat Transfer Reduction due to a Ceiling-Mounted Barrier in an Enclosure with Natural Convection

“…However, a partition (or partitions) can be used as a control parameter to reduce or enhance heat transfer and flow strength inside an enclosure [5][6][7]. The enclosures can be divided by a partition hanging from the top wall or extending from the bottom floor [8][9][10][11] or both [12][13][14] or from side walls [15][16][17][18][19][20]. The thermal state of the partition plays an important role on the heat and fluid flow in a cavity.…”

“…Thermally, a partition behaves between two limiting cases. The partition may be made of highly conductive materials, and thus the partition temperature will be at the temperature of the mounted wall [9][10][12][13][14][15][16][17][18], or the thermal conductivity of partition may be very low, and thus no temperature gradient exists between the partition surfaces and adjacent fluid [7,8]. The present study is focused on the effects of the latter partition, meaning that the thermal conductivity of partition is very low compared to the fluid thermal conductivity.…”