Natural Convection in a Vertical Rectangular Enclosure

Abstract

In this paper an experimental work has been conducted to investigate the influence of heating the lower half and cooling the upper half of vertical surface of a rectangular enclosure on natural convection. The enclosure length is (100 cm) with a square cross section (10×10 cm). The tests are done for three mass flow rates (0, 0.003 and 0.03 kg/sec) and five heat fluxes (48, 187, 400, 706 and 1080 W/m2). The hottest region formed is observed at ( = 0.67) where the lowest Nux is found while the coldest region is observed at ( = 0.33) where the highest Nux is found. Increasing the water mass flow rate enhances the heat transfer. The same thing happens with increasing the heat flux. A correlation is found to relate Nu with Ra (Nu= 0.216 Ra1/4) for (4×105≤Ra≤4×106). Both the experimental results and the correlation found are compared with a previous work and fair agreement is found.

Keywords

• natural convection
• vertical enclosure
• heating and cooling