Nanofluids flow simulasion as the flow through the porous media

Abstract

Since nanofluids combine of the base fluid and a very small amount of nanoparticles having dimensions from 1 to 100 nm, and high thermal conductivities, the nanofluids could be considered as a large amount of base fluid flowing in a high porosity media. This work presented a mathematical model which has been developed for the steady flow of the base fluid in the porous medium of the Al2 O3 nanoparticles. The flow was to be under fully developed laminar flow condition through a rectangular pipe as in the electronic circuit application. The governing equations written in terms of the primitive variables were solved through an in-house program by using the finite volume method and the SIMPLE algorithm. The effects of the simulated porosity, permeability and thermal conductivity models in the porous media were studied. The nanofluid heat transfer coefficients were changed when the porosity, permeability and thermal conductivity in the calculation were adjusted. The relationships between the nanofluid heat transfer coefficient and the distance along the rectangular pipe at different nanofluid volume fraction of 0.01% and 0.02% were presented. Firstly, the digit numbers of the porosity values did not affect the heat transfer coefficients. The wall node number providing more accuracy results; 10 wall nodes occupied by the Hamilton and Crosser model were chosen as the proper node number. The different permeability occurred in materials, which were manufactured differently and in different shapes, influenced the heat transfer coefficients differently, the more permeability the closer heat transfer coefficients to the experimental ones. Finally, the mixing thermal conductivity model which could improve the simulation performance in the previous work was examined and coupled with the porous model. The final results showed that the mixing thermal conductivity model could improve the numerical results to be closer to the experimental results trivially; by the forth digit. From this study, the developed mathematical model was found to demonstrate excellent potential in the nanofluid simulation as the porous media. © 2014, Begell House Inc. All rights reserved.