Perlite for Cryogenic Insulation

Kropschot, R. H.; Burgess, Robert W.

doi:10.1007/978-1-4757-0528-7_52

Cited by 18 publications

(6 citation statements)

References 3 publications

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“…Perlite thermal conductivity is a function of perlite density, temperature, and pressure of the background gas. Empirical data showing the effect of each of these is detailed in the work of Kropschot & Burgess, and Fulk [2] [3]. Adams formulates an analytical model built from published empirical data [4], and Geisler builds off the work of Kaganer to develop a theoretical model [5] [6].…”

Section: Experimental Data Collection/analysismentioning

confidence: 99%

“…Temperatures on the inside of the wall did not reach 245 K until the load area was reduced to 232 cm 2 (36 in. 2 ). This suggests that while it is possible to have very small areas of the inner surface below the ductility range while the entire outer surface is above the freezing point of water, the likelihood of that happening is very low because all of the liquid would need to be coursing to the inner surface in extremely narrow and focused streams, which is highly unlikely.…”

Section: Safe Removal Analysismentioning

confidence: 99%

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Annular Air Leaks in a liquid hydrogen storage tank

Krenn

Youngquist

Starr

2017

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

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Abstract. Large liquid hydrogen (LH2) storage tanks are vital infrastructure for NASA, the DOD, and industrial users. Over time, air may leak into the evacuated, perlite filled annular region of these tanks. Once inside, the extremely low temperatures will cause most of the air to freeze. If a significant mass of air is allowed to accumulate, severe damage can result from nominal draining operations. Collection of liquid air on the outer shell may chill it below its ductility range, resulting in fracture. Testing and analysis to quantify the thermal conductivity of perlite that has nitrogen frozen into its interstitial spaces and to determine the void fraction of frozen nitrogen within a perlite/frozen nitrogen mixture is presented. General equations to evaluate methods for removing frozen air, while avoiding fracture, are developed. A hypothetical leak is imposed on an existing tank geometry and a full analysis of that leak is detailed. This analysis includes a thermal model of the tank and a time-to-failure calculation. Approaches to safely remove the frozen air are analyzed, leading to the conclusion that the most feasible approach is to allow the frozen air to melt and to use a water stream to prevent the outer shell from chilling.

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Section: Experimental Data Collection/analysismentioning

confidence: 99%

Section: Safe Removal Analysismentioning

confidence: 99%

Annular Air Leaks in a liquid hydrogen storage tank

Krenn

Youngquist

Starr

2017

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

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“…9.5 are typical values for the apparent thermal conductivity of perlite versus residual gas pressure. 15 Note that minimum conductivity is achieved for pressures less than 10-2 torr. Also plotted are similar data for super- insulation.…”

Section: Insulating Materialsmentioning

confidence: 99%

Special Topics in Cryogenics

Sciver

1986

Helium Cryogenics

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“…Also they are easy to handle and maintain the thermal insulation layer. To test the thermal performance of powders, many researchers have carried out experiments to measure the effective thermal conductivity of powder insulation [1]- [7]. However, due to the irregular particle shapes, various sizes, components and densities, the prediction of the effective thermal conductivity is still a difficult mission [1].…”

Section: Introductionmentioning

confidence: 99%

Prediction of the Effective Thermal Conductivity of Powder Insulation

2015

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The powder insulation method is widely used in structural and cryogenic systems such as transportation and storage tanks of cryogenic fluids. The powder insulation layer is constructed by small particle powder with light weight and some residual gas with high porosity. So far, many experiments have been carried out to test the thermal performance of various kinds of powder, including expanded perlite, glass microspheres, expanded polystyrene (EPS). However, it is still difficult to predict the thermal performance of powder insulation by calculation due to the complicated geometries, including various particle shapes, wide powder diameter distribution, and various pore sizes. In this paper, the effective thermal conductivity of powder insulation has been predicted based on an effective thermal conductivity calculation model of porous packed beds. The calculation methodology was applied to the insulation system with expanded perlite, glass microspheres and EPS beads at cryogenic temperature and various vacuum pressures. The calculation results were compared with previous experimental data. Moreover, additional tests were carried out at cryogenic temperature in this research. The fitting equations of the deformation factor of the area-contact model are presented for various powders. The calculation results show a good agreement with the experimental results.

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Perlite for Cryogenic Insulation

Cited by 18 publications

References 3 publications

Annular Air Leaks in a liquid hydrogen storage tank

Annular Air Leaks in a liquid hydrogen storage tank

Special Topics in Cryogenics

Prediction of the Effective Thermal Conductivity of Powder Insulation

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