Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECRNashrieh Shimi va Mohandesi Shimi Iran1022-776835420170120Numerical Study of the Influence of Geometric Factors on Heat Transfer Using Water-Al2O3 Nanofluid in the MicrochannelsNumerical Study of the Influence of Geometric Factors on Heat Transfer Using Water-Al2O3 Nanofluid in the Microchannels13715025832FAHajirKarimiDepartment of Chemical Engineering, Yasouj University, Yasouj, I.R. IRANMohammad MehdiSabzehmeidaniDepartment of Chemical Engineering, Yasouj University, Yasouj, I.R. IRANJournal Article20160719<em>In this study, the heat transfer and fluid flow, </em><em>water-Al<sub>2</sub>O<sub>3</sub></em><em>nanofluid in a microchannel, two-dimensional rectangular in volume fractions 2%, 4%, 6% and 8% nanoparticles and Reynolds number from 10 to 50 using </em><em>Computational Fluid Dynamics (CFD) has been investigated. The governing equations of continuity and momentum and thermal are solved by finite element method and by applying boundary conditions by using COMSOL Multiphysics</em> <em>5.0</em><em> software. Simulation results have shown, the local Nusselt number </em><em>water-Al<sub>2</sub>O<sub>3</sub></em><em>nanofluid in Reynolds number 6.9 and volume fractions 5% is a good agreement with experimental data. Increasing the Reynolds number leads to increases fluid velocity and increase the density of streamlines in the edge of the baffle and </em><em>the creation of larger vortex flow that increases the heat transfer coefficient. By increasing the number of</em> baffles leads to the formation of the recirculation zone, which increased outlet temperatures due to better heat exchange fluid to the walls of the microchannel. So that the output of fluid temperature in Reynolds number<em> 40 in the microchannel six baffle and in the microchannel one baffle is 322.35 K and 314.9 K,</em><em> respectively. By increasing the height of baffle, increase recirculation zone and then increase the heat transfer coefficient. In six baffle microchannel for Reynolds number 50, the value of pressure drop and the nusselt number is found to be 15 and 28 higher when compared with that</em> <em>Reynolds number in 10,</em><em> respectively. But also the average output temperature is increased by increasing nanoparticle volume fractions and viscosity affected by size zone. For one baffle microchannel by rising </em><em>nanoparticle volume fractions from 0.02 to 0.1, the temperature (K) enhancing 0.56 % percent. </em><em>But the effect of the distance between the baffles, the average temperature of the microchannel output is low.</em><em>In this study, the heat transfer and fluid flow, </em><em>water-Al<sub>2</sub>O<sub>3</sub></em><em>nanofluid in a microchannel, two-dimensional rectangular in volume fractions 2%, 4%, 6% and 8% nanoparticles and Reynolds number from 10 to 50 using </em><em>Computational Fluid Dynamics (CFD) has been investigated. The governing equations of continuity and momentum and thermal are solved by finite element method and by applying boundary conditions by using COMSOL Multiphysics</em> <em>5.0</em><em> software. Simulation results have shown, the local Nusselt number </em><em>water-Al<sub>2</sub>O<sub>3</sub></em><em>nanofluid in Reynolds number 6.9 and volume fractions 5% is a good agreement with experimental data. Increasing the Reynolds number leads to increases fluid velocity and increase the density of streamlines in the edge of the baffle and </em><em>the creation of larger vortex flow that increases the heat transfer coefficient. By increasing the number of</em> baffles leads to the formation of the recirculation zone, which increased outlet temperatures due to better heat exchange fluid to the walls of the microchannel. So that the output of fluid temperature in Reynolds number<em> 40 in the microchannel six baffle and in the microchannel one baffle is 322.35 K and 314.9 K,</em><em> respectively. By increasing the height of baffle, increase recirculation zone and then increase the heat transfer coefficient. In six baffle microchannel for Reynolds number 50, the value of pressure drop and the nusselt number is found to be 15 and 28 higher when compared with that</em> <em>Reynolds number in 10,</em><em> respectively. But also the average output temperature is increased by increasing nanoparticle volume fractions and viscosity affected by size zone. For one baffle microchannel by rising </em><em>nanoparticle volume fractions from 0.02 to 0.1, the temperature (K) enhancing 0.56 % percent. </em><em>But the effect of the distance between the baffles, the average temperature of the microchannel output is low.</em>https://www.nsmsi.ir/article_25832_10d5402c9478814d9cbe23a6404012de.pdf