scholarly journals Synthesis and Effective Thermal Conductivity Measurements of Hollow Mesoporous SiO 2 Spheres for Heat‐Insulating Applications

2021 ◽  
pp. 2001048
Author(s):  
Frederik Winkelmann ◽  
Rene Albert ◽  
Michael Felderhoff
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Conductivity Measurements

Effective Thermal Conductivity Measurements of the Binary Pebble Beds by Hot Wire Method for the Breeding Blanket

1998 ◽  
Vol 34 (3P2) ◽  
pp. 877-881 ◽  
Author(s):  
Mikio Enoeda ◽  
Kazuyuki Furuya ◽  
Hideyuki Takatsu ◽  
Shigeto Kikuchi ◽  
Toshihisa Hatano
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Conductivity Measurements ◽  
Hot Wire ◽  
Wire Method

Effective Thermal Conductivity of Coal Ash Deposits at Moderate to High Temperatures

1987 ◽  
Vol 109 (2) ◽  
pp. 215-221 ◽  
Author(s):  
D. W. Anderson ◽  
R. Viskanta ◽  
F. P. Incropera
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Thermal History ◽  
Coal Ash ◽  
Physical Structure ◽  
Conductivity Measurements ◽  
Wide Range ◽  
Particulate Form ◽  
Order Of Magnitude ◽  
Deposit Structure

The effective thermal conductivity of coal ash deposits strongly influences heat transfer in pulverized coal-fired boilers. In this study thermal conductivity measurements were performed over a wide range of temperatures for fly ash, slagging deposits, and fouling deposits. The effects of ash particle size, thermal history, and physical structure of the deposit are discussed. Thermal history and deposit structure were observed to have the greatest influence on the local thermal conductivty, which increased by an order of magnitude with particle melting. Conductivities for solid-porous deposits were twice those of the same sample in particulate form.

Effective thermal conductivity of silicone/phosphor composites

2011 ◽  
Vol 45 (23) ◽  
pp. 2465-2473 ◽  
Author(s):  
Qin Zhang ◽  
Zhihua Pi ◽  
Mingxiang Chen ◽  
Xiaobing Luo ◽  
Ling Xu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Effective Thermal Conductivity ◽  
Volume Fraction ◽  
Numerical Study ◽  
Element Model ◽  
Interfacial Thermal Resistance ◽  
Conductivity Measurements ◽  
The Monte Carlo Method ◽  
Random Particle

The effective thermal conductivity of silicone/phosphor composites is studied experimentally and numerically. Thermal conductivity measurements are conducted from 30°C to 150°C for the composites with phosphor volume fraction up to 40%. In the numerical study, a finite element model with empirical particle size distribution and random particle position is constructed using a probability density function and the Monte Carlo method, and the interfacial thermal resistance layer between phases also introduced in the model. The results indicate that when phosphor concentration is below 25 vol.%, the conductivity of the composite increases slightly with either phosphor volume fraction or temperature, and the Kapitza radius of the composite is 0.8 µm. When phosphor concentration is above 25 vol.%, the increase of conductivity correlates positively with phosphor volume fraction significantly but negatively with the temperature, and the Kapitza radius is 0.032 µm.

Thermal Conductivity Measurements in Printed Wiring Boards

1997 ◽  
Vol 119 (3) ◽  
pp. 401-405 ◽  
Author(s):  
J. E. Graebner ◽  
K. Azar
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Total Thickness ◽  
Conductivity Measurements ◽  
Printed Wiring Boards ◽  
Insulating Material ◽  
High Anisotropy

The effective thermal conductivity κ of multilayer printed wiring boards (PWBs) has been measured for heat flowing in a direction either parallel (κ∥) or perpendicular (κ⊥) to the plane of the board. The conductivity of the glass/epoxy insulating material from which the boards are manufactured is anisotropic (κ∥ge ≈ 3 × κ⊥ge) and nearly three orders of magnitude smaller than the conductivity of copper. This large difference between glass/epoxy and copper produces extremely high anisotropy in PWBs that contain continuous layers of copper. For such boards, values of the board-averaged conductivity in the two directions can differ by a factor of ~100 or more. The value of κ∥ is found to depend on the ratio of the total thickness of continuous layers of copper to the total thickness of glass/epoxy, while it depends hardly at all on the amount of copper circuitry visible on the surface.

The Structure and Thermal Conductivity of Multicomponent Polymer Composites Filled with Hollow Ceramic and Silicone Microspheres

2017 ◽  
Vol 44 (7) ◽  
pp. 33-38
Author(s):  
D.P. Volkov ◽  
Yu.P. Zarichnyak ◽  
A.A. Marova
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Polymer Composites ◽  
Conductivity Measurements ◽  
Multicomponent Polymer ◽  
Independent Experimental Data

The structure of polymer composites has been investigated, and a procedure has been developed for calculating their effective thermal conductivity. Thermal conductivity measurements have been carried out, and the results of calculations have been compared with the authors' own experimental data and with independent experimental data, and also with manufacturers' data which are shown to be hundreds of percent too low.

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