Natural convective heat transfer in a square cavity with a curved hot wall partially heated from below

This study investigates laminar natural convection within a square enclosure filled with air, with a focus on understanding the impact of different geometries of a partially heated bottom wall. The study is important because optimizing heat transfer in enclosures with varying wall shapes can enhance thermal management in engineering applications. A two-dimensional numerical model was developed using the finite volume method and the Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) algorithm to solve the steady-state Navier–Stokes equations along with the mass and energy conservation equations. The study explores the effect of the Rayleigh number (Ra = 103–106), the width of the heated section (ε = 0.2–0.8), and the height of the curved shapes (h = 0.01L to 0.05L) on convection heat transfer performance. The results show that increasing the heated width (ε) and reducing the height of the curved shapes (h) significantly enhance the average Nusselt number. Specifically, for given values of ε and h, an increase in Rayleigh number leads to a further enhancement in the average Nusselt number. Moreover, the introduction of upward and downward undulations in the heated wall shape generally reduces the average Nusselt number, with downward undulations having a stronger negative effect. This work provides new insights into the influence of wall shape on heat transfer, showing that downward undulations in the heated wall diminish thermal performance, which has not been extensively explored in prior literature.