Two-dimensional analysis of low pressure flows in the annulus region between two concentric cylinders with solid fins

A finite volume code is used to solve for the steady-state two-dimensional laminar natural convection heat transfer for the gaseous low pressure flows in the annulus region between two concentric horizontal cylinders with an attached solid fin to the inner cylinder. such flows can be found in the evacuated solar collectors and in the receivers of the solar parabolic trough collectors (ptcs). boussinesq approximation is utilized to model the buoyancy effect. it is found that nusselt number (nu) depends inversely on knudsen number and directly on rayleigh number. in addition,it is found that attaching a solid fin to the inner cylinder will enhance the heat transfer for such flows. also,it is found that by increasing the tilt angle of the solid fin,then better heat transfer is achieved. finally,it is concluded that by increasing the conductivity ratio,better heat transfer is gained. © 2016 jordan journal of mechanical and industrial engineering.