Natural convection heat transfer of nanofluids in a partially divided enclosure

In this study,natural convection heat transfer of water-based nanofluids in a partially divided enclosure is investigated. governing equations are solved for partition locations of 0.2,0.4,0.6,and 0.8,partition lengths of 0.25,0.50,0.75 and 1,solid volume fractions ranging from 0-10%,and rayleigh numbers varying from 104 to 106. three different nanoparticles,cu,cuo,and al2o3,are taken into consideration,and the ratio of the nanolayer thickness to the original particle radius is taken at a fixed value of 0.1. the results show that heat transfer decreases considerably with increasing partition height. furthermore,as the distance of the partition from the hot wall increases,an initial decrease and subsequent increase is observed in the average nusselt number for low rayleigh numbers,and an initial increase and subsequent decrease is observed for high rayleigh numbers. the results also reveal that heat transfer increases considerably when nanoparticles are used and that the largest and smallest increase are obtained for cu and al2o3 nanoparticles,respectively. nanoparticle usage results in an increase in the average nusselt number up to 35% for ra=104,up to 32% for ra=105,and up to 25% for ra=106. the results also indicate that the average nusselt number increases almost linearly with solid volume fraction. © 2013 tibtd printed in turkey.