The influence of geometric parameters of baffle on the flow and heat transfer of Al2O3/water nanofluid in a tube with rectangular baffle

The aim of the present work is to investigate the role of Al2O3/water nanofluid and the geometric parameters of flow in heat transfer, pressure drop and heat exchanger efficiency. By applying periodic conditions, the flow and heat transfer of Al2O3/water nanofluid inside a tube has been investigated at the presence of heat transfer enhancer and under the influence of constant wall temperature. The turbulent flow regime and Reynolds numbers are considered to be in the range of 2000–10,000. Computational fluid dynamics software has been applied to model the governing differential equations using baffles with heights of 2, 4 and 6 mm and pitchs p/d = 0.5, 1, 2 and nanofluid with volume fractions of 1 and 2. The results of numerical modeling show that using rectangular baffle inside the pipe increases heat transfer compared to a simple pipe. As can be seen, adding nanoparticles to the base fluid increases heat transfer and by increasing the volume percentage of the nanofluid, the Nusselt number and heat transfer also increase. Moreover, increasing the volume percentage of nanoparticles from 1 to 2% increases the thermal efficiency in the heat exchanger with and without baffle. As the Reynolds number increases, the heat efficiency coefficient of the baffleless heat exchanger decreases when the Reynolds number is more than 2000. However, in the heat exchanger with baffle, increasing the Reynolds number decreases the thermal efficiency initially and then, for the Reynolds number more than 3500, an increase in thermal efficiency is illustrated. The results of the present study can be used for cooling process and heat transfer in large-scale heat exchangers and integrated circuits.