中文摘要：

针对当前低温超导电子、军事及空间探测等对液氦温区紧凑、长寿命、高可靠性制冷技术的需求,设计并研制了一台三级斯特林型脉管制冷机。讨论了制冷机第三级的回热器、脉管、调相机构等相关参数的设计,着重分析了液氦温区回热器长度与温度分布的特殊关系。实验中以He-4为工质,第三级在充压0.91 MPa,频率29.9 Hz,输入电功率100 W的工况下获得了4.97 K的最低无负荷温度,有制冷量25 mW@6 K。该结果首次证明了采用He-4为工质、以三级结构的斯特林脉管制冷机实现液氦温区制冷的可行性。

英文摘要：

A separate three-stage Stirling pulse tube cryocooler（SPTC） was designed and studied for satisfying the urgent demands of compact,long-life and reliable cryocoolers in the space and military fields.The design of the regenerator,pulse tube and phase shifter of the third stage is discussed in detail.The relationship between the length and the temperature distribution of the regenerator working below liquid helium temperature is emphatically analyzed.Finally,a bottom temperature of 4.97 K was achieved by the SPTC with helium-4 as its working gas,the cooling power was 25 mW at 6.0 K.The third stage was working at 0.91 MPa,29.9 Hz and an input power of 100 W.It is the first time that a temperature below the critical point of helium-4 is achieved by a three-stage SPTC.