Heat analysis and reduction of evaporation rate of liquid helium dewar

Kuraoka, Yasuo; Saito, K.; Nogi, Toshiharu; Misawa, Takeshi

doi:10.1016/0011-2275(79)90018-3

Cited by 7 publications

(4 citation statements)

References 3 publications

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“…Considering that the reflectivity of metal is generally sensitive to its subtle surface condition, we can safely conclude that the calculated value of P i is consistent with the experimental value. Equation (14) shows that much of the radiated power from the side at room temperature is absorbed by the duct shield despite the fact that the reflectivity of the duct and the baffles is relatively high (R = 0.950). Therefore, the main reason behind introducing baffles to reduce the heat input is that the baffles increase the number of the reflections and hence the absorption.…”

Section: Comparison With Experimental Resultsmentioning

confidence: 99%

“…Although it was considered that the radiation would be completely absorbed by the duct shield, the thermal radiation still managed to reach the cryostat by being reflected by the surface of the duct shield [13]. This phenomenon is called funneling and is also observed in the necks of liquid helium dewars [14] (x-rays also cause a similar phenomenon when passing through glass tubes, by grazing-incidence reflection [15]).…”

Section: Introductionmentioning

confidence: 99%

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Calculation of thermal radiation input via funneling through a duct shield with baffles for KAGRA

Sakakibara¹,

Kimura²,

Yamamoto³

et al. 2012

Class. Quantum Grav.

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Many studies worldwide are currently developing interferometric methods for detecting gravitational waves and one of the challenges in such methods has been to sufficiently cool the mirror in interferometric detectors in order to reduce thermal noise. Although the mirror is surrounded by a radiation shield, a hole in the shield is necessary to allow the laser beam to pass. To reduce the thermal radiation caused by the presence of the hole, we will install a duct shield with baffles. To calculate the heat input through the duct shield, we applied a ray trace model whose results were consistent with those of an experiment without baffles. As an application of our model, the heat input in the case of KAGRA (a Japanese cryogenic gravitational wave detector project) was calculated. Our analysis suggests that baffles in the duct shield can considerably reduce the heat input in KAGRA.

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Section: Comparison With Experimental Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calculation of thermal radiation input via funneling through a duct shield with baffles for KAGRA

Sakakibara¹,

Kimura²,

Yamamoto³

et al. 2012

Class. Quantum Grav.

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“… For heat in-leak through SI; layer density (N) =33 layers/cm is assumed.  It is assumed that total absorption of radiation occurs at the IV; hence funneling effect [5] is neglected.…”

Section: Numerical Modelmentioning

confidence: 99%

“…Numerical and experimental investigations of heat in-leak into cryostats, Dewars and super-insulation (SI) have been performed by many authors [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Optimum design of liquid helium dewar with vapour cooled shields

Syed¹,

Goyal²,

Atrey³

2016

Indi. Jour. of Cryog.

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The work presented aims to develop a numerical model which can be used to design a vapour shielded liquid helium (LHe) Dewar without LN2 Shield. This model can compute the position of shields and the Net Evaporation Rate (NER) based on the capacity and number of vapour cooled shields (VCS) given by the user. The effect of neck dimensions on the heat in-leak is also given by this model. Heat in-leak design calculations are done using Finite Difference Method (FDM). A computer program is developed using MATLAB®. The results can be obtained either in graphical form or in terms of minimum NER and optimal positions of the VCS. The model is validated against available results in literature and additional results are discussed in detail. This program can be extended to estimate the neck dimensions and position of shields for any given capacity, number of shields and allowable boil-off rate.

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Numerical simulation and experimental analysis of heat transfer through the neck tube into vertical cryogenic insulated cylinders

Yang

Wang

2011

Heat Mass Transfer

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Heat analysis and reduction of evaporation rate of liquid helium dewar

Cited by 7 publications

References 3 publications

Calculation of thermal radiation input via funneling through a duct shield with baffles for KAGRA

Calculation of thermal radiation input via funneling through a duct shield with baffles for KAGRA

Optimum design of liquid helium dewar with vapour cooled shields

Numerical simulation and experimental analysis of heat transfer through the neck tube into vertical cryogenic insulated cylinders

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