Theoretical study on enhancing convective heat transfer based on strengthening synergy and reducing dissipation

Convective heat transfer has three characteristics: conservation, synergy, and dissipation. Revealing their intrinsic connections and basic laws is of great significance to the development of the theory of convective heat transfer enhancement. Based on the constitutive relation and the law of conservation of energy and momentum, this study comprehensively examined the mechanism of multi-field synergy and irreversible dissipation in convective heat transfer; analyzed the relations among synergy angles of heat transfer, power consumption, and fluid inertia; proposed the thermal and exergy efficiencies reflecting irreversible dissipation during convective heat transfer; and explored the theory of convective heat transfer enhancement based on strengthening synergy and reducing dissipation. Based on this, an enhanced tube combined with V-shaped ribs and grooves was proposed, and a numerical simulation for turbulent heat transfer was performed. The V-shaped ribs and grooves on the tube wall can reduce average synergy angles of heat transfer and the inertia of the fluid in the enhanced tube compared with a smooth circular tube. The thermal and exergy efficiency exceeded 92% and 34%, respectively. The performance and efficiency evaluation criteria were 1.22–1.69 and 0.53–1.07, respectively.