Structural optimization of a latent heat storage unit with the fractal fin

Abstract

The fractal structure was applied to the fin optimization of latent heat storage (LHS) technology based on the fractal principle. By numerical simulation, the performances of LHS units with fractal tree-shaped fins were compared with those with traditional plate fins, and the effects of fin structure parameters based on the fractal principle on heat storage and release performances were studied. The results show that the heat storage performance and heat release performance of LHS units with fractal tree-shaped fins are clearly improved, and the optimal fractal structure parameters allow the LHS units to achieve optimal performance. A nonlinear surface fitting function method was used to obtain the functional relation between the branching angle and length index and the heat storage time of the LHS unit. In fractal tree-shaped fins, the optimal length index is 1.141, the optimal width ratio is 1, and the branching angle is 73.55°. In comparison to the LHS unit with traditional plate fins, the LHS unit with the optimum fractal structure parameters has a 35.85% faster melting rate and a 63.39% faster heat release rate. The least entransy dissipation, least thermal resistance and best reversibility are all characteristics of the LHS unit with the optimal fractal structure parameters.