ABSTRACT Research on passive cooling for reactor safety has drawn significant attention, with natural convection around confined cylindrical enclosures being a key focus. A computational fluid dynamics (CFD)‐based thermal–hydraulic investigation is conducted to analyze natural convection heat transfer within a 3 × 3 array of vertically heated cylinders enclosed in a water tank. The study employs a full structural detail (FSD) model, accurately representing the geometry of each heating rod to ensure close correspondence with the experimental configuration. Building upon prior single‐phase studies, the present work introduces a two‐phase alumina–water nanofluid model to examine three‐dimensional natural convection phenomena. Numerical simulations are conducted to evaluate the overall Nusselt numbers for both single‐ and symmetric‐cylinder arrangements. Comparison between experimental and CFD predictions confirms strong agreement in the Nusselt–Rayleigh number relationship, validating the numerical methodology.
Shabbir et al. (Thu,) studied this question.