Oxford Pulse Tube Incorporating COaxial Regenerator (OPTICOR)

带有同轴再生器的牛津脉冲管 (OPTICOR)

• 批准号: EP/N017013/1
• 负责人: C Stone
• 金额: $ 65.29万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FN017013%2F1
• 关键词: Oxford; Pulse; Tube; Incorporating; COaxial

Pulse tube coolers are small low temperature refrigerators that can provide cooling for electronic devices such as infra-red detectors, superconducting devices and gamma ray detection in homeland security systems. Temperatures as low as 10 K can be obtained with a single stage helium-filled pulse tube but 30 K would be more typical, as lower temperatures would use a multi-stage approach.Pulse tubes can be thought of as a Stirling cycle cooler that relies on a gas column to act as a displacer; http://en.wikipedia.org/wiki/Pulse_tube_refrigerator. A reciprocating piston (the compressor) drives a flow through a regenerator into a tube (the 'pulse tube'); heat is rejected at the interface between the compressor and the regenerator, and heat is absorbed at the other end of the regenerator. The performance of the pulse tube can be improved greatly by connecting the pulse tube to a buffer volume through an orifice or inertance tube. As this can very bulky and have limited possibilities for control, there are advantages in having a warm-end expander (in effect an oscillating piston). This can be designed to respond to the pressure variation generated by the compressor, with a phase lag and amplitude determined by the system dynamics. The pulsating flow can be produced by a system of valves with a high pressure gas supply, but this approach can only operate at low frequencies (a few Hz) due to the operation of the valves. In most recent applications a reciprocating piston is used which can be either mechanically or electromagnetically driven, and these typically operate at between 30 and 100 Hz. As the gas needs to be free of oil and other contaminants (to avoid fouling of the regenerator and cold-end heat exchanger), then it is sensible to use an 'Oxford-style' compressor. The Oxford-style compressor was developed over 30 years ago for a Stirling cycle cooler and its key features are:* a spring suspension system that is radially stiff to provide accurate linear motion of a piston in a cylinder,* a small radial clearance between the piston and cylinder (of order 8 micron) so there is negligible leakage and no contact (so no wear).* an electromagnetic drive (originally like the voice-coil of a loudspeaker).More recently compressors with moving magnets have been developed at Oxford. A crucial step was the design of a compressor in EP/E036899/1 'Development of a Miniature Refrigeration System for Electronics Cooling' that used a moving magnet with a stationary drive coil. This leads to a cheaper, low moving mass system that can operate at high frequency - this not only increases the specific output, but also leads to lower seal leakage losses and resistive losses in the drive coils. The work to be undertaken in this project will use a design that has been developed from the refrigeration compressor.The simplest pulse tubes have a linear configuration (compressor, hot-end heat exchanger, regenerator, cold-end heat exchanger, 'pulse tube' volume). But these have the disadvantage of the cold-end being in the middle so a 'U' tube arrangement is used. However, there are flow losses associated with the 'U' bend that can be eliminated by a novel radial flow and concentric tube arrangement. This will be combined with a warm-end expander, and a single dynamic balancer to provide perfect balance of the pulse tube.Stirling cycle coolers, in general, have a better performance than pulse tubes, but pulse tubes are simpler and better suited to higher frequency operation. The latest moving magnet compressor motor is capable of high frequency operation. Furthermore, high frequency operation leads to lower compressor clearance seal leakage losses, since this power loss and the Ohmic power loss are essentially independent of frequency. Therefore a pulse tube operating at high frequency (say 90 Hz) will be more efficient than at lower frequencies and be more compact than a Stirling cycle cooler.

脉冲管制冷机是小型低温制冷机，可以为电子设备提供冷却，例如红外探测器，超导设备和国土安全系统中的伽马射线探测器。单级充氦脉冲管可以获得低至10 K的温度，但30 K将是更典型的，因为更低的温度将使用多级方法。脉冲管可以被认为是一个斯特林循环冷却器，它依赖于气柱作为置换器; http://en.wikipedia.org/wiki/Pulse_tube_refrigerator。往复式活塞（压缩机）驱动气流通过回热器进入管道（“脉冲管”）;热量在压缩机和回热器之间的界面处排出，热量在回热器的另一端被吸收。通过小孔或惯性管将脉冲管与缓冲腔连接，可以大大提高脉冲管的性能。由于这可能非常庞大并且具有有限的控制可能性，因此具有热端膨胀器（实际上是振荡活塞）是有利的。这可以被设计成响应于由压缩机产生的压力变化，具有由系统动态确定的相位滞后和幅度。脉动流可以由具有高压气体供应的阀系统产生，但是由于阀的操作，这种方法只能在低频（几Hz）下操作。在大多数最近的应用中，使用往复式活塞，其可以机械地或电磁地驱动，并且这些活塞通常在30和100 Hz之间操作。由于气体需要不含油和其他污染物（以避免再生器和冷端热交换器结垢），因此使用“牛津式”压缩机是明智的。牛津式压缩机是30多年前为斯特林循环冷却器开发的，其主要特点是：* 弹簧悬挂系统，径向刚性，以提供气缸中活塞的精确线性运动，* 活塞和气缸之间的径向间隙很小（8微米量级），因此泄漏可以忽略不计，没有接触（因此没有磨损）。一种电磁驱动器（最初类似于扬声器的音圈）。最近，牛津大学研制出了带有移动磁铁的压缩机。关键的一步是EP/E036899/1“Development of a Miniature Refrigeration System for Electronics Cooling”中的压缩机设计，该压缩机使用具有固定驱动线圈的移动磁体。这导致可以在高频下操作的更便宜的低移动质量系统-这不仅增加了比输出，而且还导致驱动线圈中的更低的密封泄漏损耗和电阻损耗。在这个项目中将要进行的工作将使用一种从制冷压缩机发展而来的设计。最简单的脉冲管具有线性配置（压缩机、热端热交换器、回热器、冷端热交换器、“脉冲管”体积）。但是这些具有冷端在中间的缺点，因此使用“U”管布置。然而，存在与“U”形弯曲相关联的流动损失，该流动损失可以通过新颖的径向流动和同心管布置来消除。这将与热端膨胀器和单个动态平衡器相结合，以提供脉冲管的完美平衡。一般而言，斯特林循环冷却器具有比脉冲管更好的性能，但是脉冲管更简单并且更适合于更高频率的操作。最新的动磁压缩机电机能够高频运行。此外，高频操作导致较低的压缩机间隙密封泄漏损失，因为该功率损失和欧姆功率损失基本上与频率无关。因此，在高频（例如90 Hz）下工作的脉冲管将比在低频下工作的脉冲管更有效，并且比斯特林循环冷却器更紧凑。

项目成果

Minimising flow losses within the pulse tube of a Stirling pulse tube cryocooler

• DOI: 10.1088/1757-899x/502/1/012044
• 发表时间: 2019-04
• 期刊: IOP Conference Series: Materials Science and Engineering
• 作者: M. A. Abolghasemi;R. Stone;M. Dadd;P. Bailey;K. Liang

Coaxial Stirling pulse tube cryocooler with active displacer

• DOI: 10.1016/j.cryogenics.2020.103143
• 发表时间: 2020-10-01
• 期刊: CRYOGENICS
• 影响因子: 2.1
• 作者: Abolghasemi, Mohammad Amin;Rana, Hannah;Liang, Kun
• 通讯作者: Liang, Kun

Numerical modelling of a coaxial Stirling pulse tube cryocooler with an active displacer for space applications

• DOI: 10.1016/j.cryogenics.2020.103048
• 发表时间: 2020-03
• 期刊: Cryogenics
• 影响因子: 2.1
• 作者: H. Rana;M. A. Abolghasemi;R. Stone;M. Dadd;P. Bailey

Stirling pulse tube cryocooler using an active displacer

• DOI: 10.1016/j.cryogenics.2018.10.004
• 发表时间: 2018-12
• 期刊: Cryogenics
• 影响因子: 2.1
• 作者: M. A. Abolghasemi;K. Liang;R. Stone;M. Dadd;P. Bailey

Numerical Study on the Performance Sensitivity of a Pulse Tube Cryocooler with Active Phase Shifter

• DOI: 10.1088/1757-899x/502/1/012018
• 发表时间: 2019-04
• 期刊: IOP Conference Series: Materials Science and Engineering
• 作者: K. Liang;A. Abolghasemi;C. Stone;M. Dadd;P. Bailey