Simultaneous measurements of high-temperature total hemispherical emissivity and thermal conductivity using a steady-state calorimetric technique

Fu, Tairan; Tan, Peng; Duan, Minghao

doi:10.1088/0957-0233/26/1/015003

Cited by 8 publications

(3 citation statements)

References 58 publications

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“…The radiative cooling performance was first characterized in a vacuum environment with an apparatus (depicted in Figure b) that could evaluate the thermal radiation efficiency . (see details about the apparatus in Experimental Section).…”

Section: Resultsmentioning

confidence: 99%

A Multilayer Film Based Selective Thermal Emitter for Infrared Stealth Technology

Liang

Liu

Cheng

et al. 2018

Advanced Optical Materials

220

109

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Engineering the radiation characteristics for the design of selective thermal emitters has been a hot topic for decades and is of great value in the fields of thermophotovoltaic systems, radiative cooling, and infrared stealth. In this paper, a Ag/Ge multilayer film based selective emitter for infrared stealth is demonstrated using an ultrathin metal film and impedance matching to tune the radiation characteristics. Herein, a novel approach for infrared stealth that relies on the combination of emissivity (ε) reduction in the atmospheric windows (3–5 and 8–14 µm) and radiative cooling in a nonatmospheric window (5–8 µm) is proposed. The fabricated selective emitter has low emissivity (ε3‐5 µm = 0.18; ε8‐14 µm = 0.31) in the atmospheric windows for infrared “invisibility” and high emissivity (ε5‐8 µm = 0.82) outside the atmospheric window for radiative cooling and functions from ambient temperature to 200 °C. Compared with low‐emissivity materials, the selective emitter exhibits higher radiative cooling efficiency in vacuum and practical environments and presents lower apparent temperatures on infrared cameras. Moreover, the proposed selective emitter, with a planar and simple structure, is scalable, allowing flexible large‐area fabrication. The work demonstrates that selective emissive materials have promising applications in infrared stealth technology.

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Section: Resultsmentioning

confidence: 99%

A Multilayer Film Based Selective Thermal Emitter for Infrared Stealth Technology

Liang

Liu

Cheng

et al. 2018

Advanced Optical Materials

220

109

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show abstract

“…The system under test is brought to thermodynamic equilibrium with the measurement of specific parameters under so-called steady-state conditions. Samples should therefore be characterised by good thermal conductivity [24].…”

Section: Introductionmentioning

confidence: 99%

Emissivity measurement of black paint using the calorimetric method

2023

Archives of Thermodynamics

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The paper is of practical importance and describes the construction of a test rig and the measurement method for determining the relative emissivity coefficient of thermosensitive thin polymer coatings. Polymers are high-molecular chemical compounds that produce chains of repeating elements called 'mers'. The polymers can be natural and artificial. The former ones form the building material for living organisms, the latter -for plastics. In this work, the words plastics and polymers are used as synonyms. Some plastics are thermosensitive materials with specific physical and chemical properties. The calorimetric method mentioned in the title consists of two steps. The first stage, described here, involves very accurately measuring the emissivity of black paint with the highest possible relative emissivity coefficient, which covers the surface of the heater and the inner surface of the chamber. In the second step, the thermosensitive polymer will be placed on the inner surface of the chamber, while black paint with a known emissivity coefficient will remain on the heater. Such a way of determining the properties of thermosensitive polymers will increase the error of the method itself, but at the same time will avoid melting of the polymer coating. During the tests, the results of which are presented in this work, the emissivity coefficient of the black paint was obtained in the range of 0.958-0.965.

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“…[19] Moreover, they also developed a new method to simultaneously measure the total hemispherical emissivity and the thermal conductivity of a sample at high temperature by using steady-state calorimetry. [20] For direct measurement, emissivity is determined by comparing the emission from a sample with that from a blackbody at the same temperature and wavelength, both emissions are measured with the same detector over an identical or equivalent optical path. Since the 1990s, with the development and wide use of the Fourier transform infrared (FTIR) spectrometer, many researchers have used it to directly measure the emissivities.…”

Section: Introductionmentioning

confidence: 99%

Apparent directional spectral emissivity determination of semitransparent materials

Niu

Ren

et al. 2016

Chinese Phys. B

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An inverse estimation method and corresponding measurement system are developed to measure the apparent spectral directional emissivities of semitransparent materials. The normal spectral emissivity and transmissivity serve as input for the inverse analysis. Consequently, the refractive index and absorption coefficient of the semitransparent material could be retrieved by using the pseudo source adding method as the forward method and the stochastic particle swarm optimization algorithm as the inverse method. Finally, the arbitrary apparent spectral directional emissivity of semitransparent material is estimated by using the pseudo source adding method given the retrieval refractive index and absorption coefficient. The present system has the advantage of a simple experimental structure, high accuracy, and excellent capability to measure the emissivity in an arbitrary direction. Furthermore, the apparent spectral directional emissivity of sapphire at 773 K is measured by using this system in a spectral range of 3 µm-12 µm and a viewing range of 0 • -90 • . The present method paves the way for a new directional spectral emissivity measurement strategy.

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Simultaneous measurements of high-temperature total hemispherical emissivity and thermal conductivity using a steady-state calorimetric technique

Cited by 8 publications

References 58 publications

A Multilayer Film Based Selective Thermal Emitter for Infrared Stealth Technology

A Multilayer Film Based Selective Thermal Emitter for Infrared Stealth Technology

Emissivity measurement of black paint using the calorimetric method

Apparent directional spectral emissivity determination of semitransparent materials

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