低温光学用杜瓦柔性外壳结构热力特性研究

为了满足低温光学系统低背景、低功耗和红外探测器制冷组件高环境适应性的要求，提出了探测器制冷组件杜瓦主体（窗口、窗口帽和引线盘） 200 K低温保持，与制冷机膨胀机或脉管散热面柔性绝热连接的设计思想。针对低温光学用杜瓦柔性外壳工程应用中的特点，文中以某低温光学用长波12.5 μm 2 000元红外探测器杜瓦组件以例，提出了波纹管作为绝热连接的柔性外壳，重点阐述杜瓦柔性波纹管隔热、力学和相关漏热的设计，并开展不同热负载条件下波纹管热特性验证，可实现最小温度梯度为37.22 K，绝热热阻为1142 K/W，误差在37%。为综合评价低温光学用柔性外壳结构杜瓦组件的性能，对某低温光学用长波12.5 μm 2 000元探测器柔性外壳杜瓦组件开展热真空和鉴定级的力学试验考核验证，试验结果表明实现了200 K低温窗口，探测器60 K工作，杜瓦漏热为544 mW，低温工况工作时相对于常温工况制冷机的功耗下降了53%，并通过了4 g的随机力学考核，验证了低温光学用杜瓦柔性波纹管外壳模型合理可行，对于后续低温光学用杜瓦柔性外壳结构工程应用提供了重要参考。

Study on thermal characteristics of Dewar flexible shell structure for cryogenic optics

In order to meet the requirements of low background, low power consumption of low temperature optical system and high environmental adaptability of infrared detector refrigeration components, the design idea of the Dewar main body (window, window cap and enclosure) maintaining low temperature and flexible adiabatic connection with the cooling surface of the cryocooler expander is proposed. Aiming at the characteristics of the engineering application of the Dewar flexible shell for cryogenic optics, this paper takes a Dewar component of a long-wavelength 12.5 μm 2 000 element infrared detector for cryogenic optics as an example. This paper proposes a bellows as a flexible shell for adiabatic connection. The design of thermal insulation, mechanics and associated heat leakage of Dewar flexible bellows is highlighted. The thermal characteristics of bellows under different thermal load conditions are verified, and the minimum temperature gradient is 37.22 K, the adiabatic thermal resistance is 1142 K/W, and the error is 37%. In order to comprehensively evaluate the performance of the flexible shell structure, the thermal vacuum and qualification-level mechanical tests are carried out for a long-wavelength 12.5 μm 2 000 element detector flexible shell Dewar component for cryogenic optics. The test results show that when the low temperature window works at 200 K, the detector works at 60 K, the heat leakage of the Dewar is 544 mW. Compared with the normal temperature condition, the power consumption of the cryocooler is reduced by 53% when working in low temperature condition,, and the 4 g random mechanical test is passed, which verifies the low temperature optics. It is reasonable and feasible to use the Dewar flexible bellows shell model, which provides an important reference for the subsequent structural engineering application of the Dewar flexible shell for cryogenic optics.