The third type DC flow in pulse tube cryocooler

Zhou, Yuan; Gu, Chao; Cai, Huikun

doi:10.1007/s11431-009-0287-x

Cited by 7 publications

(8 citation statements)

References 6 publications

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“…DC gas flow in PTCs is one of the key reasons why it is more difficult to obtain a low temperature for Stirling type PTCs. The Gedeon streaming, and the third type of DC gas flow discovered [2] and verified [3] by us, are formed due to the hydrodynamic and thermodynamic asymmetry in the regenerator and other flow passages in the PTC. Based upon an improved theoretical analysis of the cause of the DC gas flow, we have carried out a series of experiments on a novel multi-bypass PTC driven by a linear compressor.…”

Section: Introductionmentioning

confidence: 73%

“…Since the regenerator can be viewed as a combination of many capillary tubes, the complicated accumulated pressure drop along the regenerator is related with not only the hydrodynamic asymmetry analyzed above but also the thermodynamic asymmetry due to the viscosity change along the regenerator discussed in our previous paper [2]. As a result, the time averaged DC flow rate is ) cos ( 2…”

Section: Improved Theorymentioning

confidence: 89%

“…In our previous papers [2,3], we have pointed out that due to the asymmetric entrance and exit effects in regenerators, the inflow and outflow mass are not equal to each other in one cycle, mainly because of the characteristics of oscillating flow, asymmetry of the structure and different local resistance losses in the refrigeration system. Here we will give a better model to concisely analyze the pressure drop in the regenerator.…”

Section: Improved Theorymentioning

confidence: 99%

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A novel Stirling type pulse tube cryocooler suppressing the third type of dc gas flow

Gu¹,

Jin²,

Zhou³

et al. 2012

AIP Conference Proceedings

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This paper analyzes the zero and first order pressure drop along the pulse tube system and presents a simple but elegant way of eliminating the third type of DC gas flow which increases the efficiency of a Stirling type PTC. Since the optimization of a PTC depends sensitively on the adjustment of the phase angle between the pressure and mass flow because of its influence on the suppression of the third type of DC gas flow, we have done a series of experiments on a Stirling type multi-bypass PTC in order to attain the lowest refrigeration temperature. After the multi-bypass PTC reaches its lowest temperature, we open the metering valve to the best degree which connects the back pressure chamber of the linear compressor to the reservoir. For this novel type of PTC, the lowest refrigeration temperature drops from 38.8 K to 25.9 K after opening the metering valve. This approach offers a promising way for a compact single stage Stirling type PTC to reach liquid hydrogen temperatures.

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Section: Introductionmentioning

confidence: 73%

Section: Improved Theorymentioning

confidence: 89%

Section: Improved Theorymentioning

confidence: 99%

See 1 more Smart Citation

A novel Stirling type pulse tube cryocooler suppressing the third type of dc gas flow

Gu¹,

Jin²,

Zhou³

et al. 2012

AIP Conference Proceedings

Self Cite

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“…Based on the power-law model fitted in range of 0.1 V/cm E 1 V/cm, LTS has a higher n value ( 25) than HTS with relatively a lower n value ( 18) due to its intrinsic and granular properties [5][6][7]. According to different n values between LTS and HTS, we firstly suggested a type of LTS/HTS hybrid composite conductor in 2004 [8] in order to improve the stability of mid-and large scale superconducting magnets, in particular the cryo-cooled conduction superconducting magnet application [9,10] .…”

Section: Introductionmentioning

confidence: 99%

Current distribution and stability of LTS/HTS hybrid superconducting conductors

Guan

Wang

Zhou

2010

Sci. China Technol. Sci.

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Current distribution and stability of a hybrid LTS/HTS superconductor, consisting of multifilamentary NbTi/Cu and Bi2223/Ag tapes, were numerically analyzed according to power-law models. The results showed that most of current passed through the LTS and the current increased in the HTS with temperature rise when the transport current was below the critical current of the hybrid conductor. The quench propagation velocity of the hybrid conductor was smaller but its minimum quench energy was larger than those of LTS conductors, indicating that the stability of the hybrid superconducting conductor was effectively improved and a high engineering current density was simultaneously achieved. Finally, a hybrid sample, made by soldering Bi2223/Ag tape onto NbTi/Cu conductor, was prepared and tested successfully at helium temperature. The experimental results qualitatively agreed with the simulated ones. distribution, hybrid conductor, minimum quench energy, quench propagation velocity, n value, stability Citation:Guan X J, Wang Y S, Zhou W W. Current distribution and stability of LTS/HTS hybrid superconducting conductors. Sci China Tech Sci

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“…Also, HTS devices are important components in future smart grids, and more and more attention is internationally paid to them. At present, many HTS apparatuses, such as cable, transformer, fault current limiter (FCL), superconducting magnetic storage (SMES), are demonstrated in live-grid [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], among which the HTS cable has operated for long term in power grid [16].…”

Section: Introductionmentioning

confidence: 99%

Progress in inhomogeneity of critical current and index n value measurements on HTS tapes using contact-free method

Wang

Guan

Zhang

et al. 2010

Sci. China Technol. Sci.

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The development of high temperature superconducting (HTS) tapes has recently made great progress, and Bi-based tapes (1 G) and YBCO coated conductor (2 G) are commercially fabricated with practical length. Application of HTS in electric power apparatuses made important achievement, various superconducting devices were demonstrated in grid, laying solid foundation for their commercialization. However, since their intrinsic microscopic defects such as weak-link, granularity, small second phase likely exist, critical current and index n value of the HTS tapes in practical length are impossible homogeneous, which have significant influences on safety, stability and efficiency of the HTS apparatuses. Therefore, critical current and index n value are two important parameters describing inhomogeneity of HTS tapes, thus two important indices for evaluating quality of practical long HTS tapes. This paper focuses on main progresses in inhomogeneity of critical current and index n value measurements on HTS tapes using contact-free methods. The statistical analytical methods evaluating the inhomogeneity of critical current and index n value are suggested. They can provide essential references for design and operation of HTS apparatuses.critical current, contact-free measurement, high temperature superconducting (HTS) tapes, index n value Citation:Wang Y S, Guan X J, Zhang H Y, et al. Progress in inhomogeneity of critical current and index n value measurements on HTS tapes using contact-free method.

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The third type DC flow in pulse tube cryocooler

Cited by 7 publications

References 6 publications

A novel Stirling type pulse tube cryocooler suppressing the third type of dc gas flow

A novel Stirling type pulse tube cryocooler suppressing the third type of dc gas flow

Current distribution and stability of LTS/HTS hybrid superconducting conductors

Progress in inhomogeneity of critical current and index n value measurements on HTS tapes using contact-free method

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