Study of heat transfer by natural convection of nanofluids in a partially heated cylindrical enclosure

In this research, a numerical study was carried out on heat transfer by natural convection of two nanofluids in a partially heated horizontal cylindrical enclosure. The partial heating occurs through the lower side of the enclosure at a constant temperature. The length of the heat source is changed from 5% to 25% of the total perimeter of the enclosure. The two side parts of the enclosure are maintained at a low constant temperature, each one of them has a length of 25% of the total perimeter. The top part of the enclosure is considered as adiabatic, it has a length of 25% of the total perimeter. The two nanofluids used are Cu-water and TiO2-water with a volume fraction of nanoparticles being varied in the range of 0-0.05. The Rayleigh number was varied in the interval 103 to 106. The results obtained were summarized in the form of correlation equations of the average Nusselt number as a function of the heated length, the Rayleigh number and volume fraction for both types of nanofluids.