Conjugate conduction-free convection heat transfer between two concentric cylinders

Abstract

Conjugate heat transfer is a coupled, fluid-structure, heat transfer problem where heat conduction in a solid wall interacts with heat convection in adjacent fluid flow. This paper examines numerically the conjugate conduction-free convection heat transfer in an annulus between two concentric cylinders. The annulus contains Newtonian fluid and is heated isothermally from its inner wall. The full governing equations of momentum and energy have been solved by using Fourier spectral method to give the details of flow and thermal fields. The effect of Rayleigh number, thermal conductivity ratio between solid inner wall and adjacent fluid and thickness of inner wall on heat transfer rate (in terms of Nusselt number) within the annulus has been examined through numerical experimentation. The heat transfer through concentric annulus increases as the thermal conductivity ratio increases. The study has also shown that the effect of inner wall thickness on heat transfer through concentric annulus depends upon the thermal conductivity ratio and Rayleigh number. For thermal conductivity ratio less than one the increase of inner wall thickness decreases the rate of heat transfer. While for thermal conductivity ratio bigger than one the increase in inner wall thickness will increase or decrease the heat transfer through concentric annulus depending upon Rayleigh number and radius ratio of the annulus.