Multiscale numerical model for high-conductivity adaptive materials mediated enhanced heat transfer between cryogenic fluid and biological tissue

Under low-temperature conditions, heat transfer between cryogenic fluids and biological tissues is constrained by multiple thermal resistances, with Kapitza resistance (or interfacial thermal resistance, ITR) being a critical limiting factor for both heat transfer efficiency and temperature uniformity. This limitation originates from significant phonon mismatch at the microscopic interface between the cryogenic fluid and biological tissues. To enhance the heat transfer process, this study introduces a high-conductivity adaptive interfacial material to reduce ITR. From a microscopic perspective, the material's effect on ITR was investigated, revealing a reduction by nearly an order of magnitude. From a macroscopic perspective, a cryogenic fluid–biological tissue coupled heat transfer model was established, incorporating the influence of microscopic ITR. The model's accuracy was validated through comparative analysis with experimental data, and the effects of external flow field parameters and interfacial layer thickness on the cooling process were examined. The high-conductivity adaptive interfacial material enables efficient cooling transfer within biological tissues, achieving rapid and uniform cooling. Meanwhile, the developed heat transfer model accurately describes the heat transfer process and provides guidance for further optimization, thereby establishing a solid practical and theoretical foundation for future cooling of large-scale tissues and organs.