Authors : Hameed K. Hamzah, Qusay Rasheed Al-Amir, Mohammed Y. Jabbar and Farooq H. Ali
Abstract: In the current research, natural convection visualization by heatline inside a square enclosure filled with or without nanofluid having concentric inner circular cylinder was numerically investigated under steady and unsteady state conditions. The nanofluid considered was copper nanoparticles dispersed in water. The vertical walls of this enclosure were cooled and the bottom wall was subjected to isoflux heating condition while the upper wall and circular cylinder were insulated. The COMSOL Multiphysics Software 5.2a was utilized to simulate the dimensionless governing equations. These equations were discretized by finite-element techniques. Calculations were achieved for solid volume fractions (0, 0.05, 0.1, 0.15 and 0.2), position of heating element (0.2L<ζ<0.5L), heating element length ratios (0.2<ε<0.8) and the Rayleigh number (103≤Ra≤06). Impermanent growth of thermal layer inside the enclosure filled with nanofluid was simulated from initial to steady state. At τ = 0.1, the maximum temperature reached its steady state for higher Rayleigh number (105-106) while for lower Rayleigh number (104) it reached to steady state when time histories increased to about 0.8. Results revealed that changing the position and length of heating element have considerable effects on isotherms, streamlines and heatlines patterns. In addition, the average Nusselt number increases with increasing the nanoparticle volume fractions for any value of Rayleigh number. This research is coincided with other available in the literature.
Hameed K. Hamzah, Qusay Rasheed Al-Amir, Mohammed Y. Jabbar and Farooq H. Ali, 2018. Natural Convection Visualization by Heatline for Nanofluids Inside a Square Enclosure Having a Concentric Inner Circular Cylinder at Isoflux Heating Condition on Bottom Wall. Journal of Engineering and Applied Sciences, 13: 11006-11023.