Investigation of Natural Convection in Partially Divided Rectangular Enclosures Both With and Without an Opening in the Partition Plate: Measurement Results

Abstract

Experimental results are presented for steady natural convection in a two-dimensional, partially divided, rectangular enclosure, in which two of the vertical walls were maintained at different uniform temperatures and the top and bottom walls were insulated. The partition plate was adiabatic, and the experiment was carried out both with and without an opening in the partition. Rayleigh numbers ranging from 106 to 108 and opening ratios of 0, 1/8, and 1/4 were investigated for an enclosure aspect ratio (length/height) of 2 and Prandtl number of 7 (for water). Local velocity and temperature measurements were made with a laser-Doppler velocimeter and thermocouple probes. Flow visualization using colored dye was also performed. Results show that there was a recirculation zone in the upper and left quadrant of the enclosure when there was no opening in the partition plate. With an opening in the partition, the recirculation zone was absent and the heat transfer rate increased. An unopened partial obstruction would reduce the heat transfer rate by an amount of 12 to 30 percent depending on the Rayleigh number. However, the opening seems to have little effect on the velocity and temperature profiles of the left-moving fluid on the bottom wall. A correlation of the Nusselt number is derived, which shows that the heat transfer rate increases as the Rayleigh number or opening ratio increases.

Internal baffles to reduce the natural convection in the voids of hollow blocks

“…Dividing the enclosure by a partition hanging from the ceiling or extending from the floor or both was studied by many researchers both experimentally (Lauriat and Desrayaud 2006;Aviram et al 2001;Gebhart et al 1988;Nansteel and Greif 1981;Nansteel and Greif 1984;Olson et al 1990;Chen et al 1990;Warrington and Ameel 1995;Bajorek and Lloyd 1982) and theoretically (Vasic et al 1991;Williams and Baker 1994;Hanjalic et al 1996;Zimmerman and Acharya 1987;Tong and Gerner 1986;Bilgen 2002). Bajorek and Lloyd (1982) presented an experimental study for natural convection in empty and baffled square enclosures.…”

“…Inserting a flow obstacle to alter the convection currents in the cavities was proposed as a means to change the rate of heat transfer across enclosures (Mezrhab et al 2006;Bilgen 2005;da Silva and Gosselin 2005;Lauriat and Desrayaud 2006;Aviram et al 2001;Gebhart et al 1988;Nansteel and Greif 1981;Nansteel and Greif 1984;Olson et al 1990;Chen et al 1990;Warrington and Ameel 1995;Vasic et al 1991;Williams and Baker 1994;Hanjalic et al 1996;Bajorek and Lloyd 1982). Mezrhab et al (2006) studied the natural convection and radiation heat transfer in a cavity having a square body at its center.…”

Natural convection in a diagonally divided square cavity filled with a porous medium

“…Turkoglu and Yucel [10] searched the effects of number of vertical partitions on natural convection inside cavities. Chen et al [11] investigated the effects of the partitions in open cavities, while Bilgen [12] studied the laminar and turbulent convection in cavities with partial partitions. Bilgen [12] found that for a small aspect ratio the heat transfer is reduced when two partitions were used instead of one partition.…”

“…The heat transfer rate through the system with partitions decreases. The types of divided cavities with partitions can be classified in three groups: (a) fully divided horizontal or vertical cavities with partition/partitions [7][8][9], (b) divided cavities with partial partitions [10][11][12][13] and (c) divided cavities with inclined partitions [14][15][16][17]. But studies on control of natural convection heat transfer via partitions are very limited for cavities filled with porous media.…”

Effects of inclination angle on conduction—natural convection in divided enclosures filled with different fluids

“…Lin and Bejan [8] conducted an experimental and analytical study to examine the natural convection in a partially divided enclosure by a partition at different heights. Chen et al [9] conducted an experiment to obtain temperature and velocity fields in water filled enclosure.…”