NUMERICAL INVESTIGATION OF FLOW AND HEAT TRANSFER OF NANOFLUIDS IN A WAVY MICROCHANNEL

摘要

The present study carries out a detailed numerical investigation of flow and heat transfer of nanofluids in a wavy microchannel. Two approaches have been chosen in the current work. The first one considers nanofluids as single-phase fluids and applies the mixture rule following from the literature for evaluating properties for the simulations. The second type of modeling is done using the discrete phase approach which involves Eulerian–Lagrangian considerations. The fluid phase is assumed to be continuous and governed by the Navier–Stokes equation. The particles are injected in this flow field, and the movement of discrete nanoparticles is determined by Newton's second law which takes into account the body force, hydrodynamic forces, and the Brownian and thermophoretic forces. Alumina–water nanofluids are chosen for the study. The results are compared with DI water. The nanofluids were found to increase the heat transfer rate compared to water. Parametric studies are carried out for different particle concentrations of 1, 3, and 5 vol.%. The particle size effect is observed for different particle sizes of 50 and 150 nm.