Constructal entransy dissipation minimization of round tube heat exchanger cross-section

Cross-section of round tube heat exchanger with porous materials is optimized by taking entransy dissipation rate minimization as optimization objective. The non-dimensional mean temperature differences of the cross-section with and without high conducting fins inserted are derived, respectively. By taking the radius ratio Rin/Rout between inner radius and outer radius as a design variable, the entransy dissipation rates are minimized. The heat transfer ability of the heat exchanger without high conducting fins inserted is improved as Rin/Rout increases, and the non-dimensional mean temperature difference decreases from 2/(3π) to 1/(3π). The heat transfer ability of the heat exchanger with high conducting fins inserted is much better than that without high conducting fins inserted, and the entransy dissipation rate varies a little when Rin/Rout apart from 1.