Untitled

Tanaka, Hirokazu; Sawai, Shinya; Morimoto, K.; Hisano, K.

doi:10.1023/a:1006670409740

Cited by 19 publications

(5 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The conductive sample was heated to steady-state and the temperatures, T T T ( , , ) l m r , at the left, middle and right positions of the investigation region in the sample were measured by thermocouples as the known conditions for the inverse solution of the energy equation. In the analysis, the investigation region is generally discretized into M sub-regions along the length direction to form M sub-region energy equations for each sub-region based on equation (2). When the thermal conductivity, λ, of the sample is known, the emissivity and the temperature distribution in the investigation region can be determined from an inverse solution of the steady-state heattransfer equations using the known temperature conditions of T T T ( , , ) l m r with M sub-region energy equations corresponding to 1 unknown emissivity and (M − 1) unknown temperatures.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, an improved method is needed to measure the total hemispherical emissivity of materials at various temperatures. The total hemispherical emissivity can be measured using radiometric [1][2][3][4][5][6] or calorimetric techniques . The calorimetric techniques are commonly used due to their simplicity and accuracy in both transient [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and steady-state measurements [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Fu¹,

Tan²,

Duan³

2014

Meas. Sci. Technol.

View full text Add to dashboard Cite

A method was developed to simultaneously measure the total hemispherical emissivity and the thermal conductivity of samples at high temperatures. The inverse problem to determine the emissivity and thermal conductivity from steady-state high-temperature calorimetric experiments was established based on models for these two quantities. The accuracy of the inverse solution was numerically analyzed for various noise levels for samples with various thermophysical properties. The simulation results illustrate that the calculation accuracies for the emissivity and thermal conductivity strongly depend on the proportions of the radiation and conduction heat fluxes in the strip sample arising from the temperature distributions in the sample. Steady-state high-temperature experiments with nickel samples were used to experimentally verify the method. The inverse solution results for the emissivity and thermal conductivity calculated from the measured data agree well with reported data in the literature. This research provides a useful reference for measuring the total hemispherical emissivity and thermal conductivity of conductive samples at high temperatures.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Fu¹,

Tan²,

Duan³

2014

Meas. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…At room temperature, it has specific heat of about 740 J/(kg K), heat conductivity of 1.38 W/(m K), and coefficient of thermal expansion of about 0.3 • 10 −6 K −1 [54]. Its emissivity is about 0.85 at room temperature, and decreases at higher temperatures [46,57].…”

Section: Fused Silicamentioning

confidence: 99%

Energy absorption through radiation in multilayer windows for spacecrafts

GALUPPI,

ROYER-CARFAGNI

2024

Preprint

View full text Add to dashboard Cite

The overall heating of satellites operating in low orbit, essentially due to direct radiation from the sun and terrestrial albedo, and the planetary radiation, is well studied, but little is found specifically on transparent plates used for windowing spacecrafts. The most historic material of choice is fused silica, as in the cupola of the International Space Station; more recently, acrylic glass is being used, but its refractive properties are poorly documented. Starting from Maxwell’s laws, the effects of electromagnetic waves incident on multilayer windows composed of panes of fused silica or acrylic glass, or a composition of these, are analyzed. Using data of refractive index from the literature, which however are incomplete and sometimes contradictory, the problem is addressed by distinguishing the frequency of the radiation, because this affects the transmissibility and absorption of each material; moreover, the frequency content of the radiation of the solar and terrestrial albedo is different from that of the planet. Worked examples show that fused silica allows most radiation to pass directly through; absorption occurs in such a thin surface layer that it can be modeled as a boundary condition. Acrylic glass, on the other hand, is characterized by absorption depending on the thickness; this can potentially increase its temperature, posing a problem since the mechanical properties decay at temperatures above 100 °C. This study represents a key step to analyze the thermal problem for space windows, of considerable interest since glazing can fail due to thermal shocks, constrained thermal variations, or temperature concentrations.

show abstract

“…5) The basic idea refers to virtual mode equations for an ionic crystal slab, 6) in which the spectral response of the slab is given as a function of emission angle, slab thickness and the dielectric response function. It is well known that the dielectric function can be derived from a Kramers-Krönig analysis of the normal spectral reflectivity.…”

Section: Introductionmentioning

confidence: 99%

“…The effects of radiation scattering in the sample were neglected in the previous study. 5) In ceramics such as zirconia in which transmission occurs at lower frequencies than in silicate glasses, the effects of transmission as well as radiation scattering in the sample may become large. However, the scattering process by grain boundaries in a ceramic sample is expected to decrease the effects of the radiation heat transfer on the values of thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

Measurements of IR Spectra and Thermophysical Properties of Tetragonal Zirconia by Thermal Radiation Calorimetry

Tanaka¹,

Sawai²,

Morimoto³

et al. 2000

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

Normal emission spectra from a clear surface of tetragonal zirconia ceramic stabilized by 5.3 wt% yttria are measured in the frequency range of 200-4500 cm −1 . The values of the hemispherical total emissivity are derived from a spectral analysis based on virtual mode equations and Kramers-Krönig relations. With these values, thermal conductivity data are obtained from measurements of temperature gradients in the sample at temperatures between 400 K and 850 K. Heat capacity measurements are carried out by quasi-static thermal radiation calorimetry. The present results are consistent with data in the literature obtained by other methods. Based on the comparison of the spectral reflectivity with the emission spectrum, it is suggested that the effects of radiation heat transfer in the ceramic sample may be compensated for by the scattering process of grain boundaries.

show abstract

Untitled

Cited by 19 publications

References 6 publications

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

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

Energy absorption through radiation in multilayer windows for spacecrafts

Measurements of IR Spectra and Thermophysical Properties of Tetragonal Zirconia by Thermal Radiation Calorimetry

Contact Info

Product

Resources

About