Nanofluid effect on forced convective heat transfer inside a heated horizontal tube

In this paper, an unsteady forced convection of two-dimensional flow of Ethylene Glycol/CNT and Ethylene Glycol/CNT-Ag in horizontal cylinder is studied. The wall is submitted to a uniform or periodic heat flux. The transient distribution of the temperature is obtained by solving, at each axial position and time, a tridiagonal system by TDMA algorithm. The convective heat transfer coefficient and bulk temperature of nanofluid are investigated versus space-time and versus different nanoparticles volume fraction. The thermal phase shift is brought out for Ethylene Glycol base fluid and EG-CNT nanofluid. The obtained results show an improving of heat transfer rate when the volume fraction increases from 0 % to 10 % of CNT. Ethylene Glycol/CNT-AG seems to be more advantageous for the enhancement of convective heat transfer than EG/CNT. The results found can be exploited for various applications especially for the enhancement performances of heat transfer rate for the absorber tube of solar collector.