Numerical analysis was performed on the natural convection heat transfer in annular interconnected cavities for laminar flow (103 ≤ Ra ≤ 107). The fin to cylinder diameter (D/d) ratio and cavity width to cylinder diameter (S/d) ratio were computed within the ranges of 2–4 and 1–5, respectively. The impact of factors such as D/d and S/d ratio on the Nusselt number is evaluated. The multi-grid algebraic solver of ANSYS Fluent is employed to execute numerical simulations of the complete governing eqns. for a cylindrical structure with interconnected cavities. The Present computational model for an interconnected cavity has been validated against the existing results. The impact of factors such as D/d and S/d ratio on the Nusselt number is evaluated. The current study determines the suitable cavity width for laminar flow to maximize heat dissipation. Temperature contour and velocity vector have been visualized for a variety of cavity configurations. The D/d ratio and S/d ratio determine the Nusselt number in annular interconnected cavities.