The Enhancement of Heat Transfer in a Two-Dimensional Enclosure Utilized with Nanofluids Containing Cylindrical Nanoparticles

The behavior of nanofluids inside a two-dimensional enclosure is numerically investigated for various pertinent parameters. A model is developed to analyze the behavior of nanofluids taking into account the cylindrical nanoparticle dispersion. The transport equations are solved numerically with finite difference approach along with the alternating direct implicit (ADI) procedure. Comparisons with previously published work on the basis of special cases are performed and found to be in good agreement. The effect of suspended carbon nanotubes on the fluid flow and heat transfer processes within the enclosure is analyzed with a theoretical model for explaining the enhancement in the effective thermal conductivity of cylindrical nanoparticles in fluids. The effects of parameters such as diameter of nanoparticle, thickness of nanolayer and volume fraction of nanoparticle have been provided in this model. Carbon nanotube in water is used with Pr = 6.2, varied Rayleigh number (10³ < Ra < 10⁵) and volume fraction (0 < f _np < 1(%)). Also, it has been shown that with decreasing the diameter of the cylindrical nanoparticle and with increasing the thickness of nanolayer, the heat transfer will be increased. Detailed results for flow pattern and heat transfer curves are presented.