Free convection from a tilted rectangular enclosure heated at the bottom wall and vented by uniform slots opening at different
walls of the enclosure was experimentally investigated. The experiments were carried out to study the effects of venting arrangement,
opening ratio and enclosure’s tilt angle on the passive cooling of the enclosure. The experiments were carried out at a constant heat
flux of 250 W/m2 and for enclosure tilt angles ranging from 0
to 180
. Three different venting arrangements of the air from the
enclosure were studied: (1) top-venting arrangement, (2) side-venting arrangement, and (3) top and side-venting arrangement. Each
venting arrangement was studied at different opening ratios of 1, 0.75, 0.5 and 0.25. The results showed that: (1) for top-venting
arrangement, the Nusselt number decreases as the tilt angle of the enclosure increases, (2) for side-venting and side and top-venting
arrangements, the Nusselt number increases as the tilt angle increases in the range [0
, 90
], then it decreases with the increase of the
tilt angle, (3) for the three venting arrangements and at any tilt angle, the Nusselt number increases with the increase of the opening
ratio of the slots, (4) for any tilt angle and at any opening ratio, the top and side-venting arrangement has the highest rate of cooling
of the enclosure, and (5) for small tilt angles, the rate of cooling of the enclosure for top-venting arrangement was higher than that
for side-venting arrangement, but with increasing tilt angle, the rate of cooling for side-venting arrangement becomes higher than
that for top-venting arrangement. Correlations were developed for the three venting arrangements to predict the average Nusselt
number of the enclosure in terms of the opening ratio and the enclosure tilt angle.