Finite element method (FEM) analysis of heat transfer by natural convection in a circular cavity containing a corrugated hollow cylinder

Purpose

The purpose of this study is to analyze the free convection phenomena arising from a temperature disparity between a cold circular cylinder and a heated corrugated cylinder.

Design/methodology/approach

Numerical simulations were used to analyze the convection patterns. The inner cylinder, made of a thermally conductive solid material, was heated through its inner surface, while the space between the cylinders was filled with air. The governing equations for velocity, pressure and temperature were solved using a Galerkin finite element method-based solver for partial differential equations.

Findings

The study explored various parameters affecting the dynamic and thermal structure of the flow, including the Rayleigh number (10³ ≤ Ra ≤ 10⁶), the number of corrugations of the inner cylinder (3 ≤ N ≤ 18), the thermal conductivity of the hollow cylinder (1 ≤ K ≤ 200) and the angle of inclination of the inner cylinder (0° ≤ φ ≤ 90°). Results indicated a notable sensitivity of flow intensity to changes in the Rayleigh number and the inner cylinder’s inclination angle φ. Particularly, for Ra = 10⁶, the average heat transfer rate increased by 203% with a K ratio increment from 1 to 100 but decreased by 16.3% as the number of corrugations increased from 3 to 18.

Originality/value

This research contributes to understanding the complex interplay between geometry, thermal properties and flow dynamics in natural convection systems involving cylindrical geometries. The findings offer useful insights for improving the transfer of heat procedures in real-world situations.