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首页> 外文学位 >Lithographically micromachined silicon/glass heat exchangers for Joule-Thomson coolers.
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Lithographically micromachined silicon/glass heat exchangers for Joule-Thomson coolers.

机译：用于焦耳-汤姆逊冷却器的光刻微加工硅/玻璃热交换器。

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摘要

Micromachined Joule-Thomson (J-T) coolers have applications ranging from cryosurgery to cooling infrared detectors. With the absence of cold moving parts, the J-T coolers can be implemented with simple structures that are suitable for silicon/glass microfabrication. The investigation proposed in this thesis focuses on the development of micromachined Si/glass heat exchangers used in the J-T coolers that operate at 200--225K when the gas pressure is 1--2MPa. The heat exchangers must maintain good stream-to-stream heat conductance between the high- and low-pressure streams while restricting stream-wise conduction to achieve a high effectiveness.;Two heat exchangers were designed, fabricated and tested. The first, a planar design, uses rows of high-conductivity silicon fins bonded onto a 100microm thick low-conductivity glass base plate. It was fabricated using a five-mask process including Si/glass/Si anodic bonding, two-step DRIE, and HF glass etching, etc. The second, a perforated-plate design, uses numerous silicon plates alternated with glass spacers. It was fabricated using a four-mask process including KOH on (110) silicon wafers, HF glass etching and anodic bonding. Platinum resistance temperature detectors were integrated into the heat exchanger for in-situ temperature sensing.;Whereas the performance of the planar heat exchanger was limited by its ability to accommodate a pressure differential across the base plate, the perforated-plate heat exchangers demonstrated a high effectiveness (0.912) in at 237--252K in effectiveness tests and good robustness at high pressures (1MPa) in J-T self-cooling tests. The temperature distribution along the heat exchanger was measured by integrated resistance temperature detectors with sensitivities of 0.26--0.30%/K at 205--296K. A J-T system using the perforated-plate heat exchanger achieved 218.7K at steady state and 200.3K in a transient state. The system provided 200mW cooling power at 228K and 1W at 239K with an estimated parasitic heat load of 300--500mW.;Finally, a flow-controlled J-T system using a perforated-plate heat exchanger and a piezoelectric microvalve was demonstrated. By modulating the flow, the microvalve could vary the cooling temperature by 5--8K around the operating points, which were 254.5K at 430kPa pressure difference in steady state, and 234K at 710kPa in transient state, without an added heat load.
机译：微型焦耳-汤姆森（J-T）冷却器的应用范围从冷冻手术到冷却红外探测器。在没有冷移动部件的情况下，J-T冷却器可以采用适用于硅/玻璃微加工的简单结构来实现。本文提出的研究重点是开发J-T冷却器中使用的微机械Si /玻璃热交换器，当气体压力为1--2MPa时，该热交换器在200--225K下运行。换热器必须在高压流和低压流之间保持良好的流到流导热性，同时限制流向传导，以实现高效率。设计，制造和测试了两个热交换器。第一种是平面设计，使用的是成排的高导电硅鳍片，这些鳍片粘合在100微米厚的低电导率玻璃基板上。它是使用包括Si /玻璃/ Si阳极键合，两步DRIE和HF玻璃蚀刻等在内的五种掩膜工艺制造的。第二种是穿孔板设计，使用了许多硅板和玻璃垫片。它是使用四掩膜工艺制造的，包括在（110）硅晶片上的KOH，HF玻璃蚀刻和阳极键合。铂电阻温度检测器集成到热交换器中以进行原位温度感测;虽然平面热交换器的性能受到其适应基板两端压差的能力的限制，但多孔板热交换器表现出很高的性能在237--252K的效率测试中具有0.912的有效性，在JT自冷测试中在高压（1MPa）下具有良好的鲁棒性。沿热交换器的温度分布由集成电阻温度检测器测量，在205--296K的灵敏度为0.26--0.30％/ K。使用多孔板热交换器的J-T系统在稳态时达到218.7K，在瞬态时达到200.3K。该系统在228K时提供200mW的冷却功率，在239K时提供1W的冷却功率，估计的寄生热负荷为300--500mW。最后，展示了使用多孔板式换热器和压电微阀的流量控制J-T系统。通过调节流量，微型阀可以在工作点附近将冷却温度变化5--8K，在稳态时430kPa压差下为254.5K，在瞬态下710kPa时为2344.5K，而无需增加热负荷。

著录项

  • 作者

    Zhu, Weibin.;

  • 作者单位

    University of Michigan.;

  • 授予单位 University of Michigan.;
  • 学科 Engineering Electronics and Electrical.;Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 160 p.
  • 总页数 160
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 无线电电子学、电信技术;机械、仪表工业;
  • 关键词

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