Parameter optimization of unevenly spiderweb-shaped fin for enhanced solidification performance of shell and tube latent-heat thermal energy storage units

Abstract

This paper investigates the solidification process of fin-strengthened shell and tube latent-heat thermal energy storage unit (LTESU). An unevenly spiderweb-shaped fin is proposed to fit better with shell and tube structures. This new type of fin is connected to the radial fins by annular fins. The uneven arrangement is achieved by varying the distance between the annular fins and the width ratio of the annular fin to the radial fin. Numerical simulation is used to investigate the strengthening effect of the novel fin on the solidification performance of LTESU. Moreover, to achieve better solidification properties, three parameters of the spiderweb-shaped fin are optimized for an equal share of metal fins (the position of the outermost annular fin γ, decreasing common difference of distance between annular fins ψ, and width ratio δ). The results show that there are optimum values for all three parameters to enable LTESU to achieve the shortest complete solidification time and the highest thermal energy release rate (TERR). The optimized spiderweb-shaped fin has a structure with larger annular fin spacing close to the inner tube, smaller annular fin spacing away from the inner tube, and thicker radial fins, thinner ring fins. It is recommended that the configuration parameters for the spiderweb-shaped fin are γ = 0.94, ψ = 0.05, and δ = 0.10. Compared to conventional rectangular fins, it ultimately reduces the complete solidification time by 88.9 % and increases the TERR by 7.8 times.