Heat radiation reduction in cryostats with multilayer insulation technique

Singh, D. B.; Pandey, Ashutosh; Singh, M. K.; Singh, L.; Singh, Vakil

doi:10.1088/1748-0221/15/07/p07032

Cited by 7 publications

(13 citation statements)

References 26 publications

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“…Multilayer insulation techniques are often designed in the thermal protection systems to make the heat loads within an acceptable limit. The decrement is analyzed in the value of the heat load, which is coming from the hot wall of the cryostat to the cold wall of the cryostat after implementing the MLI technique [4]. Hence, a good care of MLI technique is required for its better and fruitful performance.…”

Section: Resultsmentioning

confidence: 99%

“…Present work considered that the outer and inner walls of the cryostat are buildup with mechanically polished copper [22] and the exchange of heat load is from the outer hot wall to the inner cold wall of the cryostat. Copper is selected for this purpose because of having a low value of emissivity as compared to Aluminium after proper mechanical polishing and it rarely brittles even at very low temperatures [4]. The expression for the heat load q 1−2 to the inner wall of the cylindrical cryostat (without inserting any layer) can be expressed as [23]:…”

Section: Cold Wall Boundarymentioning

confidence: 99%

“…The heat load q 1−2 after inserting a single intermediate layer of the same material with surface area A 3 (such that A 1 > A 3 > A 2 ), emissivity ε 3 and temperature T 3 (the average temperature of the hot and cold boundaries), in between the two walls of a cylindrical cryostat can be expressed as [4]:…”

Section: Cold Wall Boundarymentioning

confidence: 99%

“…Thus, the radiation and thermal conduction both heat load flux moves through the first spacer as well as to the second radiation shield. This process is successively continued till the cold wall boundary and results in a great decrement in the radiation heat load [4]. A schematic diagram representing the working principle of MLI technique is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…These reflective layers are usually coated with Aluminium (also Gold or Silver) on both the sides to achieve the high value of reflective performance [5]. The radiation shields which are typically used in many MLI performances are Double Aluminized Kapton [6], Gold coated ceramic foils [1], Double Aluminized Mylar (DAM) [4] and Aluminium foils [5]. There are many spacers used in various MLI performances like Vegetable fiber, Nomex [6], Carbon fibrous, Alumina fibrous, Amorphous carbon [1], Terylene film, Polyester spacers [2], Dacron, Glass−tissue, Silk−net [7], Refrasil, Dexi glass, Silica fiber felt [5] etc.…”

Section: Introductionmentioning

confidence: 99%

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Improvement in the performance of multilayer insulation technique and impact in the rare physics search experiments

Singh,

Chaubey

et al. 2021

Preprint

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Providing thermal insulation to systems at very low temperature from surroundings, involves blocking the transport of thermal energy−regular or enhanced, taking place through radiative, conductive and convective processes. For instance, the enhancement of radiative heat transport that takes place by infra−red or far infra−red light at low temperature is due to diffractive propagation. The wavelength of light in this part of the spectrum usually lie in the range of mm to cms. Hence it can get bent across an obstacle while propagating forward. Apart from radiative, the convective and conductive processes also get affected due to appearance of non−linearities in the modes of lattice vibrations and anomalies in material transport due to the appearance of vorticity and turbulence in the intervening media. The Multilayer insulation (MLI) technique has offered a robust thermal protective mechanism to provide proper insulation to the cold walls of the cryostats from the heat of the surroundings (basically the radiation heat load). This work is focussed on the estimation of performance and efficiency of the MLI technique as well as exploration of its versatile applicability. Three different spacer materials such as Dacron, Glass−tissue, and Silk−net with radiation shields are selected for the intervening medium in the present study. This article explores the thermal performance of MLI system by changing the physical parameters (emissivity and residual gas pressure), varying the geometry of the radiation shields (perforation styles of radiation shields) and by analyzing the effect of arrangement of radiation shields on the conduction heat load. The predictions of analytical models−Modified Lockheed equation, Lockheed Martin Flat Plate equation and McIntosh's approach are compared for the performance of MLI systems and for the applicable choice in future experiments. This analysis is concluded by studying the possibility of using MLI technique in the health sector by reducing the evaporation rate of liquid Oxygen (LO 2 ) during pandemic situations e.g., in COVID−19.

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Section: Resultsmentioning

confidence: 99%

Section: Cold Wall Boundarymentioning

confidence: 99%

Section: Cold Wall Boundarymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%