Measurement of Total Hemispherical Emittance on Spacecraft Thermal Control Coatings

Ramasamy, A.; Sundaresan, N. K.; Padmanabhan,; Gupta, P. P.; Murthy, H. Narayana

doi:10.4271/921329

Cited by 4 publications

(1 citation statement)

References 2 publications

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“…As observed in figure 8(b), the time required to reach thermal equilibrium is approximately 100 min in Aeroglaze Z306. The measured emissivity value of Aeroglaze Z306 was found to be 0.80 at 82 K, which is close to the reported values (∼0.65 to ∼0.8) [35][36][37][38]. Further, the emissivities of the PU1 and SG121FD were measured at 82 K, which were 0.78 and 0.74, respectively.…”

Section: Resultssupporting

confidence: 85%

The development of a novel apparatus to measure the emissivity of high-roughness materials at 82 K

Dewasi,

Gangradey,

Mukherjee

et al. 2023

Meas. Sci. Technol.

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Emissivity of a material changes with temperature. The knowledge of emissivity plays an important role in the estimation of radiation heat load in cryogenic systems. As the values of emissivity of different materials at cryogenic temperature are scarcely available in literature, room temperature emissivity values are extensively used to estimate radiation heat load in a cryogenic system. This might lead to a significant deviation between the predicted and actual radiation properties at cryogenic temperature. Therefore, in the present work, an apparatus is developed based on calorimetric technique for measuring emissivity of an opaque material around 82 K. The novelties of the apparatus are compact size, ease of sample handling, lower time required to reach thermal equilibrium and most importantly, capacity to measure emissivity of a sample of high roughness. To understand the effectiveness of low and high emissivity coated heat radiators for the system, a theoretical as well as an experimental approach has been followed. It is found that the high emissive heat radiator led to a significant reduction in the time required to reach the thermal equilibrium as compared to a low-emissive heat radiator. To verify and validate this setup, emissivity of the Aeroglaze Z306 (high emissivity) and Cu (low emissivity) is measured and compared with the values reported in the literature. Finally, the work has been extended to measure emissivity at cryogenic temperature for the first time for PU1, SG121FD, and the indigenously developed novel materials such as black paints, adhesive and activated charcoals of different granule sizes.

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Section: Resultssupporting

confidence: 85%

The development of a novel apparatus to measure the emissivity of high-roughness materials at 82 K

Dewasi,

Gangradey,

Mukherjee

et al. 2023

Meas. Sci. Technol.

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Thermal studies on electrodeposited black oxide coating on magnesium alloys

2001

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Thermal behavior of black anodic coatings on magnesium alloy, AZ31B and magnesium lithium alloy, MLA 9 has been investigated. The chemical nature of coating is characterized by infrared spectral studies. The thermoanalytical investigations have been carried out using thermogravimetry (TG), derivative thermogravimetry (DTG), and differential scanning calorimetry (DSC). The decomposition proceeds through three steps viz., dehydration, decomposition of chromium hydroxide and sulphate and decomposition of magnesium chromate to oxide. Measurement of hemispherical emittance of coatings verses temperature was investigated using calorimetric methods. The studies revealed that the thermal emittance of coatings increases with temperature. #

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Measurement of Total Hemispherical Emittance of Spacecraft Thermal Control Coatings at Low Temperatures

Yenni

Ambirajan

Sundaresan

et al. 2012

Heat Transfer Engineering

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Measurement of Total Hemispherical Emittance on Spacecraft Thermal Control Coatings

Cited by 4 publications

References 2 publications

The development of a novel apparatus to measure the emissivity of high-roughness materials at 82 K

The development of a novel apparatus to measure the emissivity of high-roughness materials at 82 K

Thermal studies on electrodeposited black oxide coating on magnesium alloys

Measurement of Total Hemispherical Emittance of Spacecraft Thermal Control Coatings at Low Temperatures

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