Hydrodynamic resistance parameters of regenerator filler materials at cryogenic temperatures

Perrella, M.; Ghiaasiaan, S. Mostafa

doi:10.1016/j.cryogenics.2021.103320

Cited by 3 publications

(5 citation statements)

References 21 publications

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“…The variations in charge pressure and cold end heat exchanger temperature are analyzed and reported by Perrella et al, [12]. The values of operating pressure and minimum temperature for the revised model fall within the specified range, and hence acceptable to be directly employed.…”

Section: Tablementioning

confidence: 89%

“…As this model is having limitation of the experimental validation, another model from literature [15] is simulated by integrating appropriate resistance values for oscillating flow at cryogenic temperature. The selected are valid over the specified range of operating pressure and cold end heat exchanger temperature [12]. This simulation of complete cryocooler reports steady state cycle average temperature of 32.2 K at the cold end heat exchanger with oscillatory flow at cryogenic temperatures.…”

Section: Discussionmentioning

confidence: 99%

“…The preliminary model is validated by solving the above equation in CFD. Furthermore, the values of resistances for oscillating flow at room temperature as well as at cryogenic temperatures are also reported in literature [9,12]. Thus, two more cases are developed to analyze the effect of these resistance values on the performance of cryocooler.…”

Section: Model Developmentmentioning

confidence: 99%

“…To overcome these limitations, experimental and numerical analysis of the regenerator are performed and resistance values for oscillating flow at room temperature for various regenerator filler material are calculated [9][10][11]. The further investigations report about these resistance values for oscillating flow at cryogenic temperatures [12]. While performing CFD analysis, considering the local thermal equilibrium against non-equilibrium between the wire mesh material of porous media and working fluid yields the lower cycle average temperature of cold end, which is having negligible temperature difference with nonequilibrium condition at the cost of huge amount of time and computational facility [13].…”

Section: Introductionmentioning

confidence: 99%

“…Oscillating Flow at room temperature[9] 1.56 10 10 67000Case 2 Oscillating Flow at cryogenic temperature[12] 1.68 10 10 29700…”

mentioning

confidence: 99%

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Numerical Investigations about Flow Resistance Values for Stirling Type Pulse Tube Cryocooler

Joshi¹,

Tendolkar²

2022

CFDL

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Pulse tube cryocoolers are extensively used for space application because of simplicity and reliability in operation. Many researchers have attempted the numerical analysis of the oscillatory flow inside the cryocooler, however, the precise predictions of the exact behavior of the gas inside the cryocooler using CFD has not yet been reported. While performing the CFD analysis of cryocooler, the values of inertial and viscous resistance coefficients play vital role and highly contributes to the pressure drop taking place in porous media. The prime objective of present work is to analyze the effect of these resistance values on performance of cryocooler. A single stage Stirling type pulse tube cryocooler model from literature is employed to perform the CFD analysis and the results obtained from the analysis are validated to ensure that methodology used for analysis is correct. The resistance values mentioned in the literature are applicable for steady and unidirectional flows. The model is further modified for the values of resistances for oscillating flow at room temperature and oscillating flow at cryogenic temperature. It is observed that performance predictions for oscillating flow at cryogenic temperature resistance values yields substantially lower temperature than all other cases. As experimental validation of this model is still not reported in literature, the reliability of accurate resistance values is not confirmed. Hence, another model of single stage Stirling type pulse tube cryocooler from literature is numerically analyzed for various operating conditions and is compared with its experimental performance, and found to be in fair agreement.

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Section: Tablementioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Model Developmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Oscillating Flow at room temperature[9] 1.56 10 10 67000Case 2 Oscillating Flow at cryogenic temperature[12] 1.68 10 10 29700…”

mentioning

confidence: 99%

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Numerical Investigations about Flow Resistance Values for Stirling Type Pulse Tube Cryocooler

Joshi¹,

Tendolkar²

2022

CFDL

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Thermal Conductivity of Some Ceramic Materials at Cryogenic Temperatures

Ghavami

Ghiaasiaan

2022

ASME Journal of Heat and Mass Transfer

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The application of 3D printable ceramics in cryogenic systems is expanding. Thermophysical properties of these ceramics in cryogenic temperatures are thus needed. In this investigation the thermal conductivities of 7740 Pyrex, 99.99% purity dense Alumina, and dense 8% mol Ytrrium-stabilized zirconia (YSZ) were experimentally measured in the 75 to 300 K temperature range, using the guarded comparative-longitudinal heat flow technique in accordance with ASTM International's ASTM E1225-13 standard. These ceramics are widely applied in cryogenics systems, including some critical components of Stirling and pulse-tube cryocoolers. The measured conductivities for Pyrex are in general agreement, but slightly higher than available published data. The data for 99.99% purity dense Alumina agree with data from two previously published sources in the aforementioned temperature range. Our experimental thermal conductivity data for dense 8% mol YSZ appear to be the first such data in the aforementioned temperature range and indicate a temperature-sensitive distribution with a peak at about 140 K temperature. The data also converge with two sets of previously published experimental data representing temperatures lower and higher than the aforementioned temperature range. Empirical correlations are developed for the thermal conductivity of 7740 Pyrex and 99.99% - purity dense Alumina for the 75 to 300 K temperature range based on our experimental data. Empirical correlations are also proposed for the 40 to 400 K temperature range for 8% Mol YSZ, based on the experimental data generated in this work as well as data from two other sources.

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Hydrodynamic and Heat Transfer Characteristics of Miniature Stirling Cryocooler Regenerators — A Review

Kumar¹

2021

Int. J. Air-Cond. Ref.

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Miniature Stirling coolers are preferred to provide cryogenic cooling for infra-red (IR) sensors used for communication, military, and space applications. They provide 0.25–1.5[Formula: see text]W of cooling effect at 60–80[Formula: see text]K. Miniature Stirling coolers used for space applications are time tested, reliable, and have the maximum COP compared to other types of coolers. Helium is used as the working fluid because of its low boiling point, high thermal conductivity, high ratio of specific heat, and inert gas properties. A regenerator is the primary heat exchanger in the system, which periodically exchanges heat with the cold and hot gases passing through the regenerator material. The effectiveness of the regenerator is the most important parameter influencing the cooling effect produced by the system. For the optimum performance of the cryocooler, the regenerator should have maximum heat transfer area, minimum void volume, minimum pressure drop, large heat capacity ratio between the matrix material and gas, and minimum longitudinal conduction. Since some of these requirements are conflicting in nature, the design of the regenerator becomes a challenge in the overall design of the cooler. A state-of-the-art review of regenerator materials, designs, and operation is presented in this study. The different sources of regenerator losses and the issues related to regenerator design and optimization are discussed in detail. Results of various experimental and numerical investigations conducted on a Stirling regenerator are discussed and the recent developments in material selection and design are highlighted.

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Hydrodynamic resistance parameters of regenerator filler materials at cryogenic temperatures

Cited by 3 publications

References 21 publications

Numerical Investigations about Flow Resistance Values for Stirling Type Pulse Tube Cryocooler

Numerical Investigations about Flow Resistance Values for Stirling Type Pulse Tube Cryocooler

Thermal Conductivity of Some Ceramic Materials at Cryogenic Temperatures

Hydrodynamic and Heat Transfer Characteristics of Miniature Stirling Cryocooler Regenerators — A Review

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