Total hemispherical emissivity of glass sheets with different thicknesses measured by a transient calorimetric technique

Sasaki, Seizi; Kou, Heung; Masuda, Hidetoshi; Kiyohashi, Hiroshi

doi:10.1068/htjr116

Cited by 7 publications

(1 citation statement)

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“…where 𝜎 is the Stephan-Boltzmann constant, and 𝜀 8 is the thermal emittance of silica quoted from Ref. 40 , as shown in supplementary information section S3. This model has been proven valid for black ceramic particles with the particle sizes < ~ 600 μm 11,39 .…”

Section: C． Modeling Of Effective Thermal Conductivitymentioning

confidence: 99%

Thermal conductivity modeling of monodispersed microspheres using discrete element method

Zeng

Chung

Zhang

et al. 2021

Journal of Applied Physics

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Particle beds are widely used in various systems and processes, such as particle heat exchangers, granular flow reactors, and additive manufacturing. Accurate modeling of thermal conductivity of particle beds and understanding of their heat transfer mechanisms are important. However, previous models were based on a simple cubic packing of particles which could not accurately represent the actual heat transfer processes under certain conditions. Here, we examine the effect of the packing structure on thermal conductivity of particle beds. We use monodispersed silica microspheres with average article sizes ranging from 23 to 330 µm as a model material. We employ a transient hot-wire technique to measure the thermal conductivity of the particle beds with packing density of 43 to 57% within a temperature range of room temperature to 500℃ and under N2 gaseous pressures of 20 to 760 Torr. We then use a discrete element method (DEM) to obtain the realistic packing structure of the particles, which is then fed into a finite-element model (FEM) to calculate the thermal conductivity, with the consideration of solid conduction, gas conduction, and radiation heat transfer. Our results show that the thermal conductivity model based on the more realistic random packing structure derived from the DEM shows better agreement with the experimental data compared to that based on the simple cubic packing structure. The combined DEM and FEM methodology can serve as a useful tool to predict effective thermal conductivity of particle beds and to quantify different heat transfer mechanisms under various conditions.

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Section: C． Modeling Of Effective Thermal Conductivitymentioning

confidence: 99%