HEAT TRANSFER IN A SQUARE CAVITY FILLED WITH TITANIA NANOFLUID

The current work focusses on the natural convection developed in a square cavity with differentially heated vertical walls, filled with nanofluid. The nanofluids under consideration is in base fluids water, EG and oil. Thermophysical properties namely specific heat and thermal conductivity have been evaluated for all the three base fluids for volume fractions 1%-10% . Results from these evaluations have been used to estimate the Nusselt numbers along the hot wall, for varying volume fractions, using the correlations derived from literature. Effect of the Rayleigh number which is representative of the difference in the temperature between the two walls, on the Nusselt number, has also been investigated. It is concluded that the Nusselt number increases as the volume fraction of the nanoparticle increases. Further, convection heat transfer mode is activated at a lower volume fraction for water nanofluid compared to EG and oil nanofluids. Increase of Nusselt number with volume fraction implies that the addition of titania nanoparticles delays the onset of convection, implying that the system becomes unstable for higher Rayleigh numbers in comparison to the base fluids.