CFD Investigation of Finned Tube Heat Exchanger using Nano Fluids

In the present work laminar cross flow convective heat transfer of nano fluids over tube banks with circular geometry under constant wall temperature condition is analyzed. Nano fluid instead of pure fluid as external cross flow is used due to its potential to increase heat transfer rate of the system. The effect of nano fluid on compact heat exchanger performance is studied and compared with that of conventional system. The two dimensional steady state Navier-Stokes equations and the energy equation governing laminar incompressible flow are solved using a finite volume method for the case of flow across an in-line bundle of tube banks as commercial compact heat exchanger. The Nano fluid used was Al2O3 water 1%,2% and 3% and the performance was compared with water. In this paper, the effect of parameters such as tube shape circular and heat transfer comparison between Nano fluid and pure fluid is studied. Temperature profile, heat transfer coefficient and pressure profile, Nusselt Number were obtained from the simulations and the performance was discussed in terms of heat transfer rate and performance index. The increase in Reynolds number caused an increase in the heat transfer rate and a decrease in the overall bulk temperature of the cold fluid.