Heat transfer investigation of laminar developing flow of nanofluids in a microchannel based on Eulerian-Lagrangian approach

In this article, laminar forced convection of nanofluids in a parallel plate microchannel under constant wall temperature is numerically investigated. A Eulerian-Lagrangian two-phase method is employed to simulate the flow and heat transfer of nanofluid in the microchannel. Navier-Stokes equations were solved using a finite difference method based on the projection algorithm while a Runge-Kutta method have been used to solve Lagrangian equations of the particle phase. A parallel code is developed on a cluster of processors which indicates a good performance to solve an Eulerian-Lagrangian problem. The convective heat transfer coefficient of nanofluids is better than the base fluid particularly in the entrance region. The results based on two phase modelling, show a slightly greater improvement in the heat transfer coefficient in comparison to the homogeneous single-phase nanofluid method. The obtained results show that the heat transfer enhancement increases as the nanoparticles volume fraction increases, and decreases with the Reynolds number for Cu-water nanofluid, while the alumina-water nanofluid have a different behaviour. A comparison of two different nanofluids showed the importance considering all of the nanofluid's properties not just thermal conductivity.