Numerical prediction of laminar nanofluid flow in rectangular microchannel

Abstract

Numerical simulation of laminar nanofluid flow in Three-dimensional (3D) straight rectangular microchannel heat sink is carried out. In this study the behavior and effect of using pure water and Fe3O4-H2O as working fluids in the microchannel are examined. Fe3O4-H2O with volume fraction range of 0.4% - 0.8% are used in this simulation to evaluate the cooling performance of microchannel heat sink. Fluent, a Computational Fluid Dynamic (CFD) is used as the solver of simulation. A rectangular microchannel with hydraulic diameter of 86 µm and length of 10mm under the boundary condition of constant heat flux and uniform inlet velocity is set on this analysis. The Results of present work show that using Fe3O4-H2O as coolant resulted in to higher efficiency of heat transfer in microchannel heat sink in comparison to Pure water. However, using Fe3O4-H2O with 0.8% volume fraction provide a high heat transfer enhancement of 30% as compared to 0.4% and 0.6% volume fractions of the same Fe3O4-H2O. Numerical results show that increasing the thermal conductivity of working fluid can enhanced heat transfer. Therefore, it is equally important to note that the presence of nanoparticles could enhance the cooling of MCHS. Meanwhile, higher Nusselt number is found as fluid enters the channel inlet. This could be anticipated as a result of the development of thermal entry region at the channel and the values of Nusselt number tend to stabilize after fully develop region has been achieved.