Periodic natural convection in a nanofluid-filled enclosure with oscillating heat flux

This paper examines the periodic natural convection in an enclosure filled with nanofluids. Whilst a heat source with oscillating heat flux is located on the left wall of the enclosure, the right wall is maintained at a relatively low temperature and the other walls are thermally insulated. Based upon numerical predictions, the effects of pertinent parameters such as Rayleigh number, solid volume fraction, heat source position, type of nanoparticles and oscillation period are examined. A periodic behaviour is found for the flow and temperature fields as a result of the oscillating heat flux. The utilisation of nanoparticles, in particular Cu, enhances the heat transfer especially at low Rayleigh numbers. In addition, the oscillation period of heat generation affects the maximum operational temperature of the heat source. It is also interesting to observe that the optimum position of the heat source on the left wall is a function of Rayleigh number. The results of this study can be used in the design of an effective cooling system for electronic components to help ensure effective and safe operational conditions. (C) 2009 Elsevier Masson SAS. All rights reserved.