laminar mixed convection of al2o3-water nanofluid in a three-dimensional microchannel

the fluid flow and heat transfer in a three-dimensional microchannel filled with al2o3- water nanofluid is numerically investigated. the hybrid scheme is used to discretize the convection terms and simpler algorithm is adopted to couple the velocity and pressure field in the momentum equations. the temperature fields, variation of horizontal velocity along the centre line of the channel, average nusselt number and the thermal resistance in different aspect ratios are presented. it is observed that aspect ratio mainly affected the temperature gradient as well as heat transfer. analyzing the results of numerical simulations indicates that with increasing aspect ratio, horizontal velocity along the centre line increased and then, average nusselt number and the inlet and outlet thermal resistance decrease in the microchannel.