Numerical simulation study on the cooling process of bionic tree-shaped cold storage plate

With the rapid development of the cold chain logistics industry and the continuous expansion of the demand for energy conservation and emission reduction, phase change cold storage technology has become a hot research direction. This paper integrated bionic structures into advanced heat transfer technology, in terms of the thermal resistance-dominated mechanism of phase change material （PCM） freezing process, embedded tree-shaped channels into the cold storage plate to enhance its energy storage density. A numerical model was established using COMSOL to verify the advantages of this tree-shaped channels for the flow and heat transfer characteristics. Energy storage rate, dynamic changes of the phase interface, and the temperature distribution within the cold storage plate were analyzed under different cooling conditions. The results indicate that the tree-shaped structure inherently exhibits favorable flow resistance characteristics. By employing a multi-stage fractal design, the fluid generates vortices that thin the thermal boundary layer. Additionally, the structure creates zoned multi-directional heat transfer units within the cold storage plate, thereby enhancing energy storage efficiency. Higher heat transfer fluid （HTF） flow rate and lower temperature can enhance energy storage rate and reduce dead zones proportion, but they also increase phase change material freezing rate variation and worsen surface temperature uniformity. Considering the energy storage rate and temperature distribution, an optimal cooling condition is identified at 1.73 L/min and -26 °C, yielding volumetric cold energy rate of 10.98 kW·m⁻³, and temperature standard deviation within 2 K.