Author:
Corcione Massimo,Natale Antonio,Quintino Alessandro,Spena Vincenzo Andrea
Abstract
Buoyancy-driven convection from a heated vertical plate suspended inside a nanofluid-filled square enclosure cooled at the walls, is studied numerically using a two-phase model based on the double-diffusive approach. The study is conducted under the assumption that the 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. The system of the governing equations of continuity, momentum and energy for the nanofluid, and continuity for the nanoparticles, is solved
by a computational code which incorporates three empirical correlations for the evaluation of the effective thermal conductivity, the effective dynamic viscosity and the coefficient of thermophoretic diffusion, all based on a high number of literature experimental data. The SIMPLE-C algorithm
is used to handle the pressure-velocity coupling. Numerical simulations are executed using alumina-water nanofluids for different values of the diameter and the average volume fraction of the suspended nanoparticles, the plate length and position, the cavity width, the average temperature
of the nanofluid, and the temperature difference imposed between the plate and the boundary walls of the enclosure. It is found that the impact of the nanoparticle dispersion into the base liquid increases remarkably with increasing the average temperature, whereas, by contrast, the other
controlling parameters have just moderate effects. Moreover, when the top and bottom walls of the enclosure are cooled, keeping the sidewalls adiabatic, a periodic flow is detected, whose main features will be discussed.
Publisher
American Scientific Publishers
Subject
Fluid Flow and Transfer Processes,Mechanical Engineering