Free convection in ZnO-Water nanofluid-filled and tilted hemispherical enclosures containing a cubic electronic device

The present work deals with free convection within nanofluid-filled hemispherical enclosure whose base (disc) can be inclined with respect to the horizontal plane by an angle ranging from 0° to 180° (horizontal disc with dome facing upwards and downwards respectively). A cubic active electronic component positioned at the center of the disc generates important heat fluxes leading to high Rayleigh number values ranging from 5.21 × 107 to 7.29 × 1010. The used nanofluid is a mixture Water-ZnO with a volume fraction varying between 0 (pure water) and 10%. The 3D numerical approach is done by means of the volume control method based on the SIMPLE algorithm, and using a one-phase model. The dynamic and thermal fields are presented for several geometric and thermal configurations. The natural convective heat transfer is quantified by means of the average Nusselt Number whose evolution versus the inclination angle, the Rayleigh Number and the volume fraction is presented and commented on for all considered cases. Correlations of the Nusselt-Rayleigh-Prandtl-inclination angle type are proposed to determine the natural convective heat transfer in this assembly corresponding to applications in electronics.