Toward Understanding of Mixed Convection Flows From the Spinning Finned Sphere Available to Purchase

This work elucidates a rigorous numerical analysis of predicting the fluidic behavior and pattern of thermal field around the rotating finned sphere suspended in ambient air. Mixed convection analysis is carried out within the laminar regime by considering important pertinent factors, such as fin height $(0.1≤h/D≤0.33)$⁠, fin spacing $(0.0719≤S/D≤0.7786)$⁠, Rayleigh number $(102≤Ra≤105)$⁠, and strength of rotational field $(0≤Re≤300)$⁠. A low-temperature zone within the spacing between the fins is predicted to form when $Re≠$ 0 compared to $Re=$ 0 and this fluidic behavior is clearly understood employing velocity vectors. Thus, the heat removal rate is predicted to be higher in the spinning condition than nonspinning case. The heat transfer rate $(Q)$ grows continually with the reduction of $S/D$ and reaches a maximum magnitude till a certain lower value of $S/D$ then it starts to drop dramatically. The maximum peak point of $Q$ is gradually shifts toward the lower value of $S/D$ as the magnitude of $Re$ is higher. We have also characterized the behavior of average $(Nu)$ and local $(Nul)$ Nusselt number. Behavior of $Nu$ witnesses an increasing trend as $S/D$ grows for a given $h/D$⁠, $Ra$⁠, and $Re$⁠. A steeper increasing pattern of $Nu$ against $S/D$ at a higher $Re$ compared to a lower $Re$⁠. Finally, a suitable correlation for average Nusselt number was developed using pertinent parameters which shows a satisfactory agreement with numerical data.