Experimental analysis of free warm expander pulse tube

Brito, M.C.; Peskett, G. D.

doi:10.1016/s0011-2275(01)00160-6

Cited by 15 publications

(6 citation statements)

References 1 publication

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“…The secondary pulse tube is more desirable due to the fact that it requires much smaller swept volumes than the secondary regenerator. [5][6][7][8] The secondary regenerator was a stainless steel tube 44.5 mm in length with an inside diameter of 3.40 mm and packed with 200 mesh copper screen with a porosity of about 0.67. The hydraulic diameter was about 0.108 µm.…”

Section: Resultsmentioning

confidence: 99%

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Experiments with linear compressors for phase shifting in pulse tube crycoolers

Lewis¹,

Bradley²,

Radebaugh³

2012

AIP Conference Proceedings

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For the past year NIST has been investigating the use of mechanical phase shifters as warm expanders for pulse tube cryocoolers. Unlike inertance tubes, which have a limited phase shifting ability at low acoustic powers, mechanical phase shifters have the ability to provide nearly any phase angle between the mass flow and the pressure. We discuss our results with experiments and modeling on a commercially available miniature linear compressor operating as an expander on the warm-end of a 4 K pulse tube, whose temperature is nominally about 35 K. We also present results on experiments with a linear compressor operating at room temperature but coupled to the 4 K stage through secondary regenerators and secondary pulse tubes. Experiments on a small pulse tube test apparatus with both 4 He and 3 He showed improved efficiency when using the mechanical expander over that of inertance tubes. Phase locking techniques using function generators and power amplifiers for control of phase angle are detailed. The use of expanders demonstrates flexible control in optimizing phase angles for improved cryocooler performance.

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Section: Resultsmentioning

confidence: 99%

“…[4][5][6][7] Figure 2 shows two types of mechanical phase shift mechanisms that are used in regenerative cryocoolers. Commercially available pressure oscillators can be used for the warm-end expander when the warm-end of the pulse tube operates at ambient temperature.…”

Section: Phase Shiftersmentioning

confidence: 99%

Experiments with linear compressors for phase shifting in pulse tube crycoolers

Lewis¹,

Bradley²,

Radebaugh³

2012

AIP Conference Proceedings

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“…Matsubara and Miyake [8] and Brito and Peskett [9] proposed the use of passive phase shifters with a moving plug at room temperature. Later, [10,11] introduced the use of an active phase shifter that is controlled and synchronized with the main drive.…”

Section: Low Temperature Pulse Tube Cooler Operationmentioning

confidence: 99%

Innovative phase shifter for pulse tube operating below 10 K

et al. 2016

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“…The method advised below may be thought of as a modification of the "dual-slope" calorimetry as is used for the evaluation of heat capacities by making a direct comparison of the heating and cooling rates of a sample, as explained in [5][6][7][8][9]. In the modified technique, we will compare the heating rates during warm up of an initially precooled cold finger in the pilot Simulation Dewar under different trial added heat loads.…”

Section: Introductionmentioning

confidence: 99%

Warm-up calorimetry of Dewar-Detector Assemblies

Veprik

Shlomovich

Tuito

2015

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. Boil-off isothermal calorimetry of Dewar-Detector Assemblies (DDA) is a routine part of their Acceptance Testing Procedure. In this approach, the cryogenic liquid coolant (typically LN2) is allowed to naturally boil-off from the Dewar well to the atmosphere through a mass flow meter; the parasitic heat load is then evaluated as the product of the latent heat of vaporization and the "last drop" boil-off rate. An inherent major limitation of this technique is that it may be performed only at the fixed boiling temperature of the chosen liquid coolant. A further drawback is related to the explosive nature of "last drop" boiling, manifesting itself as an uneven flow rate. This especially holds true for advanced High Operational Temperature Dewar-Detector Assemblies, typically featuring short cold fingers and working at 150 K and above. In this work, we adapt the well-known technique of dual-slope calorimetry and show how accurate heat load evaluation may be performed by comparing the slopes of the warm-up thermal transients under different trial added heat loads. Because of the simplicity, accuracy and ability to perform calorimetry literally at any temperature of interest, this technique shows good potential for replacing traditional boil-off calorimetry.

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Experimental analysis of free warm expander pulse tube

Cited by 15 publications

References 1 publication

Experiments with linear compressors for phase shifting in pulse tube crycoolers

Experiments with linear compressors for phase shifting in pulse tube crycoolers

Innovative phase shifter for pulse tube operating below 10 K

Warm-up calorimetry of Dewar-Detector Assemblies

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