随着空间科学技术的不断发展，4K温区制冷技术已经成为制约SIS/HEB超导和远红外探测器的器件应用的瓶颈。针对目前空间、军事等领域对4K温区小功率微型制冷机的迫切需求，本项目针对高频4K脉冲管制冷机微型化过程中非理想热力学循环这一关键科学问题进行研究。通过理论分析、数值模拟和实验等方法的互相验证，研究液氦温区非理想热力学过程，探究极低温非理想条件下微型脉冲管制冷机的工作机制和流程，解决极低温条件下流动与热力过程的高效耦合、极低温条件下回热器高效换热以及小压比下热力循环等关键问题，研制出达到4K温区的微型化脉冲管制冷机样机。样机的研制成功将极大的推动我国空间深低温技术的发展，为开展深空探测、THz通信和空间科学等技术的实验提供技术基础。

With the development of space science technology, the 4K refrigeration technology has become a bottleneck problem of restricting the development of SIS/HEB superconducting detectors and far-infrared detector. For the need of current space, military, and other areas with low input power, miniature and 4K, non-ideal thermodynamic cycle of high-frequency 4K pulse tube cryocooler will be investigated. Theoretical analysis, numerical simulation and experimental verification will be combined to investigate the non-ideal thermodynamic cycle and the working mechanism and process of miniature pulse tube cryocooler with the case of very low temperature and non-ideal condition, solve the key problems of efficient coupling between the oscillating flow and thermodynamic processes in a very extremely temperature conditions, high efficient heat exchange of regenerator with extremely temperature and thermodynamic cycle with small pressure ratio, manufacture the prototype of miniature 4K multi-stage pulse tube cryocooler. Successful development of a prototype will greatly promote the development of China's deep space cryogenic technology, which provide a technical basis to carry out deep space exploration, the THz communications and space science experiments..