Transient conjugate free convection within flexible enclosure having discrete heat source

Abstract

Transient conjugate free convection in flexible enclosure is examined numerically. Isoflux heat sources are mounted in a left wall of finite thermal conductivity while a right wall is assumed to be hyper-flexible. The finite element method (FEM) is adopted to solve the governing partial differential equations, an arbitrary Lagrangian–Eulerian (ALE) approach inherent in the unstructured mesh. The governing parameters under consideration are: the number of the heat source, 1 ≤ n ≤ 3 , the thickness of the heat source, 0 ≤ a ≤ 0 . 25 , and the Rayleigh number, 10 5 ≤ Ra ≤ 10 8 . It is determined that the development of conjugate convection heat transfer experiences through an initial phase, a transition phase, and a steady state phase. Each phase interval is shifted by adjusting the thickness of the heat source. Higher number and thicker of heat source cases had an ignorant effect on the shape of the flexible wall, but they tend to suppress the heat transfer rate. Increasing the block amplitude by 25% for n = 1 , 2 , 3 results in reductions of the values of Nu ¯ to 24%, 20%, and 28% respectively.