提高波纹管式制冷器稳定性的设计

针对波纹管式自调节流制冷器普遍存在稳定性差的问题,通过对此类制冷器最核心的部件——波纹管自调机构的受力分析,对制冷器的预留位移量这个核心参数进行优化设计,增强了制冷器的自调能力,从设计上避免制冷器不自调或流量变化现象的发生,改善了长期困扰自调式制冷器的间歇性喷液现象,提高了制冷器的稳定性,并通过实验得到了论证。     

影响自调式J-T制冷器启动时间的因素

在芯片和杜瓦结构确定后,对自调式J-T制冷器的研究是研制快启动焦平面红外探测器的重要工作。实验研究了热交换管长度、气源压力、流量对制冷器启动时间的影响。通过对实验结果的分析,阐述了回流阻力和自调机构受力对制冷器工作过程的影响,加深了制冷过程的理解,实验结论对研制快启动制冷器有一定帮助。     

锥形自调式节流制冷器的应用研究

介绍了一种应用于红外焦平面探测器组件上的自调式节流制冷器,该制冷器为锥形结构,采用了一种新型自调方式,与传统的波纹管型自调式节流制冷器相比,具有制冷速度快、结构简单、成本低廉、装调方便等优点;文中还对该制冷器自调机构的工作原理进行了简单的介绍和分析,并对该型制冷器进行了性能测试。     

自调式J-T制冷器波纹管高温焊接的研究

波纹管是波纹管自调式J-T制冷器自调机构的核心元件,其焊接后性能直接决定着自调机构的性能及可靠性。本文从刚度、硬度、微观组织形貌等多个方面,对自调式J-T制冷器中常用的电沉积波纹管,由于高温焊接过程中不同的热量输入、不同的冷却方式对波纹管焊接后性能造成的影响,开展了相关的研究。     

记忆合金在节流制冷器中的应用

介绍了一种红外探测器上所应用的新型节流制冷器,该制冷器采用形状记忆合金(Shape Memory Alloy)作为自调机构的调节元件;与传统波纹管型自调式制冷器相比,具有结构简单、装调方便、寿命长、稳定性好等优点;文中还对记忆合金工作原理、制冷器结构及低温记忆合金现状和前景等进行了简要的介绍和分析。     

波纹管型自调式J-T制冷器充气参数设计研究

在制冷器总体结构和波纹管设计已确定的条件下,讨论了充气腔充气参数设计。理论分析了充气腔工质采用氩气的优势;实验验证了充气腔工质采用氩气不仅可以有效提高启动时间,而且有利于提高制冷器控温精度;通过自调机构受力分析,确定了最小预留量和最低充气压力的计算方法;在理论计算基础上,实验确定了某型号制冷器的充气腔充气压力。     

自调式节流制冷器充气腔分析

自调式节流制冷器充气腔分析航空工业总公司○一四中心王三煜自调式制冷器灵敏度的关键是与自调机制密切相关的。在自调系统诸多关联要素中，充气腔结构、充气介质及介质参数起着举足轻重的作用，中文拟对此作些分析。自调式节流制冷器充气腔分析@王三煜...     

进气压力及流量对自调型J-T制冷器性能的影响

针对因高压流体进气压力及流量变化造成制冷器运行不稳定的问题,基于热平衡方程法,建立制冷器内换热器及自调机构的理论模型,分析不同高压流体进气压力及流量对自调型J-T制冷器运行性能的影响规律。结果表明：节流前高压流体的总压降及节流后低压流体的干度随进气压力增加而减小,随流量增加而增大;随着进气压力及流量变化,制冷器制冷量存在峰值;当高压流体进气压力增加或流量减小,制冷器冷段区域范围逐渐减小;当换热器结构一定,随着进口压力及流量改变,阀针插入深度及其锥角具有最优值。对于本文研究的制冷器结构,当质量流量小于0.1 g/s时,可忽略高压流体入口压力变化(20～30 MPa)对阀针插入深度范围的影响。     

一种锥形自调式J-T制冷器北大核心CSCD

介绍了一种既可以实现快速启动又能够维持长时间小流量工作的锥形自调式J-T制冷器,可以广泛应用于制导导弹中红外焦平面探测器组件的制冷。该J-T制冷器采用微型波纹管作为自调机构,具有成本低、适应范围广等特点。与探测器杜瓦组件进行耦合试验,结果表明在50 MPa氩气气源条件下,芯片降温至100 K所需时间≤5 s。     

一种提高波纹管型自调式J-T制冷器控温精度的设计及试验研究

为提高波纹管型J-T制冷器的控温精度,对阀针进行了优化设计.在阀针针尖部位开槽,使其与制冷器阀体上的主节流孔形成双节流孔.制冷器开启后,工质进入主节流孔,节流降温;制冷器自调后,阀针完全堵住主节流孔,稳定小流量从针槽喷出.通过试验确定了阀针开槽的合理尺寸范围.试验结果表明,阀针开槽可以有效提高制冷器的控温精度.     

微型低温制冷技术的现状和发展趋势

介绍了目前典型的军用第二代、第三代焦平面探测器杜瓦制冷机组件中斯特林制冷机和节流制冷器的应用情况,从焦平面探测器芯片探测元尺寸的变化,提出了配接制冷机的冷指尺寸的变化,介绍了昆明物理研究所微型低温制冷技术的发展现状及微型低温制冷机向高可靠性、低成本、高工作温度的发展趋势。     

一种测试半导体制冷器的瞬态方法

ZT值、最大制冷温差和响应时间是表征半导体制冷器性能的重要参数.文中介绍了一种能同时测量这三个参数的瞬态方法,并讨论了热沉对测试结果的影响.利用一个由恒流脉冲发生器和数据采集卡组成的简单测试系统测得制冷器在小电流下的电阻电压和塞贝克电压,通过这两个电压推导出ZT值、最大制冷温差.这种瞬态方法是非接触式测量,准确度高,可用于薄膜热电器件测试;另外瞬态方法耗时短,可大大缩短半导体制冷器可靠性测试的周期.采用这种方法对4mm×4mm×2.4mm的热电制冷器进行实验,环境温度300K时,测得ZT值为0.39,最大温差58.5K,响应时间20s.     

Loss mechanisms in single-mode fibers jacketed with a loose jelly-filled tube

A study has been made of temperature induced losses in single-mode fibers with a loose jelly-filled jacket. It has been found that at low temperatures where the fiber has to buckle to fit into the tube, the losses have the character of macrobend losses. At high temperatures where the fiber is pressed against the tube wall, the losses are of the microbending type.     

应变自组装InAlAs量子点材料和红光量子点激光器

通过提高量子点材料的质量和优化量子点激光器材料的结构 ,研制出高质量的应变自组装 In Al As/Al Ga As/Ga As量子点材料和低温连续激射的红光量子点激光器。器件性能达到国际同类研究的最好水平     

辐射制冷技术在中国气象卫星上的应用

配置红外探测通道的光学遥感仪器是气象卫星的主要载荷之一,我国太阳同步轨道和地球静止轨道气象卫星的光学载荷采用辐射制冷器冷却红外探测器及其后的光学部件,使其在规定的温度工作。概要介绍了我国风云系列气象卫星对制冷技术的要求以及近30年来所研制的不同型式辐射制冷器,给出了FY-1A～1D、FY-3A、FY-2A～2E气象卫星辐射制冷器的在轨飞行性能,阐述了辐射制冷技术在气象卫星上长期业务应用的关键技术和实际结果。探讨了辐射制冷技术在我国未来气象卫星上的应用前景。     

Universal Control on Pyroresistive Behavior of Flexible Self‐Regulating Heating Devices

Smart heating devices with reliable self‐regulating performances and high efficiency, combined with additional properties like mechanical flexibility, are of particular interest in healthcare, soft robotics, and smart buildings. Unfortunately, the development of smart heaters necessitates managing normally conflicting requirements such as good self‐regulating capabilities and efficient Joule heating performances. Here, a simple and universal materials design strategy based on a series connection of different conductive polymer composites (CPC) is shown to provide unique control over the pyroresistive properties. Hooke's and Kirchhoff's laws of electrical circuits can simply predict the overall pyroresistive behavior of devices connected in series and/or parallel configurations, hence providing design guidelines. An efficient and mechanically flexible Joule heating device is hence designed and created. The heater is characterized by a zero temperature coefficient of resistance below the self‐regulating temperature, immediately followed by a large and sharp positive temperature coefficient (PTC) behavior with a PTC intensity of around 10⁶. Flexibility and toughness is provided by the selected elastomeric thermoplastic polyurethane (TPU) matrix as well as the device design. The universality of the approach is demonstrated by using different polymer matrices and conductive fillers for which repeatable results are consistently obtained.     

A Comparison of Performance Characteristics of Multistage Thermoelectric Coolers Based on Different Ceramic Substrates

The influence of the thermal properties of the substrate on the performance of cascade thermoelectric coolers (TECs) is studied with an emphasis on a justified choice of substrate material. An analytical model is developed for predicting the thermal resistance of the substrate associated with three-dimensional heat transfer from a smaller cascade area into a larger cooling cascade. The model is used to define the maximum temperature difference for a line of standard multistage TECs based on various substrate materials with different thermal conductivities, including white 96% Al₂O₃ “Rubalit” ceramic, grey 99.8% Al₂O₃ “Policor” ceramic, and AlN and BeO ceramics. Two types of multistage TECs are considered, namely with series and series–parallel connection of TE pellets, having from two to five cascades with TE pellet length in the range from 0.3 mm to 2 mm. A comparative analysis of the obtained results is made, and recommendations are formulated concerning the selection of an appropriate substrate material providing the highest performance-to-cost ratio.     

某星载CCD器件散热用热电制冷器的性能试验

某地球静止轨道卫星光学相机由于CCD 器件功耗较大,并要求处于较低的工作温度水平,经论证确定采用热电制冷器对CCD的温度进行主动控制。设计了热电制冷器性能地面试验装置,分别在大气和真空环境中选用国内外不同型号的热电制冷器进行对比试验研究。试验得到了安装方式对冷热端温差的影响、输入功耗与冷热端温差的对应关系、负载功率与冷热端温差的对应关系以及大气和真空环境对制冷器的性能影响等数据。试验结果表明,在CCD负载下,制冷器冷热端的温差最大可达到45.8℃,能够满足CCD的低温工作需求。     

Self‐Assembling,Bioinspired Wax Crystalline Surfaces with Time‐Dependent Wettability

One of the most fascinating properties of materials in nature is the superhydrophobic and self‐cleaning capabilities of different plant surfaces. This is usually achieved by the hydrophobic cuticles that are made of cutin and contain wax crystals both within them and on their surfaces. Here, bioinspired n‐hexatriacontane wax films are deposited via thermal evaporation and it is shown that the surface evolves in time via self‐assembly. This leads to a dramatic change in the wetting properties with a transition from hydrophobic to superhydrophobic characteristics, which takes place within several days at room temperature. This phenomenon is investigated and strain‐induced recrystallization is proposed to be the mechanism for it. This work could become the basis for the inspiration and production of tuned, time‐dependant, temperature‐sensitive, variable‐wettability surfaces.     

新型无TEC的非制冷IRFPA读出电路研究

为了降低非制冷红外焦平面阵列的功耗,研究了去除热电制冷器（TEC）等温度稳定装置的读出电路。通过对微测辐射热计的电阻温度特性的分析,设计了一种新型无需温度稳定装置的读出电路,该电路的Flash存储器存储不同温度下的校正系数,温度传感器实时检测探测器的环境温度,从Flash中取出相应的温度校正系数送入数模转换器(DAC),通过DAC的电压输出来控制探测器偏流以进行环境温度补偿。HSPICE模拟结果表明,电路输出与探测器工作的环境温度无关,系统的总功耗下降了80%,同时电路噪声保持在一个较低的水平。