In the present study, natural convection heat transfer inside a trapezoidal enclosure filled with carbon
nanotube–EG–water nanofluid using variable properties has been numerically investigated. The bottom
and top walls of trapezoidal enclosure are kept at constant temperaturesThandTc, respectively, while the
side walls of the cavity are thermally insulated. Using the finite volume method and the SIMPLER algorithm, the governing equations have been discretized. Simulations have been carried out for different
aspect ratios, Rayleigh numbers of 10
3
–10
6
as well as solid volume fractions of 0.0015, 0.03, and 0.045.
The results show that at low Rayleigh numberðRa610
4
Þ, the average Nusselt number NuAvgdecreases
with increasing the inclination angle (aspect ratio) at all solid volume fractions. While forRa=10
6
, the
NuAvgincreases and then decreases with inclination angle (aspect ratio) with maximum NuAvgoccurring
atc¼30
. Moreover, NuAvgincreases with increasing Rayleigh number at fixed inclination angle (aspect
ratio) and solid volume fraction.
