Use of nanofluids as coolants in buoyancy-driven thermal management of embedded heating components of small-scale devices

A two-phase model based on the double-diffusive approach is used to perform a numerical study on natural convection of water-based nanofluids in square cavities partially heated at the bottom wall and cooled at both sides, assuming that Brownian diffusion and thermophoresis are the only slip mechanisms by which the solid phase can develop a significant relative velocity with respect to the liquid phase. Numerical simulations are basically executed for Al2O3 + H2O, using the diameter and the average volume fraction of the suspended nanoparticles, the cavity width, the heated fraction of the bottom wall, the average temperature and the temperature difference imposed across the cavity, as independent variables. Additional simulations are also performed using CuO or TiO2 nanoparticles. It is found that the cooperation between the solutal and thermal buoyancy forces results in a significant enhancement of the heat transfer performance of the nanofluid compared with the pure base liquid.