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Go to Editorial ManagerThe optimal spacing between elliptic tubes cooled by free convection is studied numerically. A row of isothermal elliptic tubes are installed in a fixed volume and the spacing between them is selected according to the constructal theory (Bejan's theory). In this theory the spacing between the tubes is chosen such that the heat transfer density is maximized. A finite volume method is employed to solve the governing equations; SIMPLE algorithm with collocated grid is utilized for coupling between velocity and pressure. The range of Rayleigh number is (103 ? Ra ? 105), the range of the axis ratio of the tubes is (0 ? ? ? 0.5), and the working fluid is air (Pr =0.71). The results show that the optimal spacing decreases as Rayleigh number increases for all axis ratios, and the maximum density of heat transfer increases as the Raleigh number increases for all axis ratios and the highest value occurs at axis ratio (? =0) (flat plate) while the lowest value occurs at (? =0.5) (circular tube). The results also show that the optimal spacing is unchanged with the axis ratio at constant Rayleigh number.
A substantial amount of research has been dedicated to improving the efficiency of heat exchangers, which are extensively utilized in electronic equipment, heating and air conditioning systems, space vehicles, thermal power systems, industrial applications, and transportation. Enhancing the efficiency of these devices can lead to significant reductions in materials, cost, and space. Constructal design offers a promising approach to optimizing various heat transfer systems, including electronic packages, by applying the constructal law to achieve optimal configurations. This review aims to examine recent advancements in the application of constructal design theory to heat exchangers and its potential for enhancing thermal performance. The most recent state-of-the-art developments are thoroughly described, along with their evaluating parameters, and recommendations for further research in this field are provided.
The optimal spacing between finned tubes cooled by free convection is studied numerically. A row of isothermal finned tubes are installed in a fixed volume and the spacing between them is selected according to the constructal theory (Bejan's theory). In this theory the spacing between the tubes is chosen such that the heat transfer density is maximized. A finite volume method is employed to solve the governing equations; SIMPLE algorithm with collocated grid is utilized for coupling between velocity and pressure. The range of Rayleigh number is (103 ? Ra ? 105), the range of the tube position is (0.25 ? ? ? 0.75), and the working fluid is air (Pr =0.71). The results show that the optimal spacing decreases as Rayleigh number increases for all tube positions, and the maximum density of heat transfer increases as the Raleigh number increases for all tube positions and for Ra=105 the highest value of heat transfer density occurs at tube position (? =0.75) while the lowest value occurs at tube position (? =0.25). The results also show that the optimal spacing remains constant with change of the tube position at constant Rayleigh number.