Numerical simulation of natural convection heat transfer of a nanofluid in an L-shaped enclosure with a heating obstacle

The natural convection heat transfer in an L-shaped enclosure being filled with Al2O3/water nanofluid and having an internal heating obstacle is presented in this paper by LBM. The combination of the three topics (L-shaped cavity, hot obstacle and nanofluid) is the main novelty of the present study. The statistics focused specifically on the effects of different key parameters same as Ra number (10(3)-10(6)), aspect ratio of the channel (0.2-0.6), nano-particle volume fraction of (0-0.05), position and height of the hot obstacle and nanoparticle diameter (20-80 nm) on the heat transfer inside the L-shaped enclosure. The average Nusselt numbers were also calculated for the obstacle sides. The obtained results showed that the streamlines and isotherm lines had different patterns at different Ra numbers, aspect ratio and the height of obstacle. The heat transfer phenomena were highly affected by the heating obstacle position. With the nanofluid and the reducing AR, the increasing Ra number, the decreasing nanoparticle diameter and the increasing height of the obstacle, an increase in the heat transfer and the individual Nusselt number appeared. Moreover, the maximum Nusselt number was observed when the heating obstacle was located in the lower position inside the left wall. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.