A Benchmark Study of Burning Rate of Selected Thermites through an Original Gasless Theoretical Model

This paper describes a kinetic model dedicated to thermite nanopowder combustion, in which core equations are based on condensed phase mechanisms only. We explore all combinations of fuels/oxidizers, namely Al, Zr, B/CuO, Fe2O3, WO3, and Pb3O4, with 60 % of the theoretical maximum density packing, at which condensed phase mechanisms govern the reaction. Aluminothermites offer the best performances, with initiation delays in the range of a few tens of microseconds, and faster burn rates (60 cm s−1 for CuO). B and Zr based thermites are primarily limited by diffusion characteristics in their oxides that are more stringent than the common Al2O3 barrier layer. Combination of a poor thermal conductivity and efficient oxygen diffusion towards the fuel allows rapid initiation, while thermal conductivity is essential to increase the burn rate, as evidenced from iron oxide giving the fastest burn rates of all B- and Zr-based thermites (16 and 32 cm·s−1, respectively) despite poor mass transport properties in the condensed phase; almost at the level of Al/CuO (41 versus 61 cm·s−1). Finally, formulations of the effective thermal conduction coefficient are provided, from pure bulk, to nanoparticular structured material, giving light to the effects of the microstructure and its size distribution on thermite performances.

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Influence of the Material and Thickness of the Specimen on an Infrared Stress Image

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.261-263.1641 ◽

2004 ◽

Vol 261-263 ◽

pp. 1641-1646

Author(s):

Kenji Machida ◽

Mamtimin Gheni

Keyword(s):

Thermal Conductivity ◽

Hybrid Method ◽

Thermal Conduction ◽

Crack Problem ◽

High Stress ◽

High Accuracy ◽

Problem Analysis ◽

Principal Stresses ◽

Distribution Form ◽

Stress Components

The thickness dependency of the temperature image obtained by an infrared thermography was investigated using specimens with three kinds of materials and four kinds of the thickness of the specimen. Only the sum of the principal stresses which is the first invariant of stress tensor is measured, and it is impossible to measure individual stress components directly. Then, the infrared hybrid method was developed to separate individual stress components. Although the form of the contour line of low stress side differs greatly, the distribution form of high stress side was considerably alike. The stress intensity factor of material with low thermal conductivity can be estimated with high accuracy by the infrared hybrid method. On the crack problem, it was elucidated that the influence of thermal conduction is large and an inverse problem analysis is required.

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A theoretical model for effective thermal conductivity of multicore power cables

Electric Power Systems Research ◽

10.1016/j.epsr.2012.01.006 ◽

2012 ◽

Vol 87 ◽

pp. 10-12 ◽

Cited By ~ 4

Author(s):

G. De Mey ◽

V. Chatziathanasiou

Keyword(s):

Thermal Conductivity ◽

Theoretical Model ◽

Effective Thermal Conductivity ◽

Power Cables

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Thermal conduction characteristics of silicone composites including ultrasonic-treated graphite

Journal of Composite Materials ◽

10.1177/00219983211059582 ◽

2021 ◽

pp. 002199832110595

Author(s):

Weontae Oh ◽

Jong-Seong Bae ◽

Hyoung-Seok Moon

Keyword(s):

Thermal Conductivity ◽

Ultrasonic Treatment ◽

Thermal Conduction ◽

Light Emitting Diode ◽

Thermal Interface Material ◽

Ultrasonic Power ◽

Lighting System ◽

Thermal Interface ◽

Light Emitting ◽

Inorganic Oxides

The microstructural change of graphite was studied after ultrasonic treatment of the graphite. When the graphite solution was treated with varying ultrasonic power and time, the microstructure changed gradually, and accordingly, the thermal conductivity characteristics of the composite containing the as-treated graphite was also different with each other. Thermal conductivity showed the best result in the silicone composite containing graphite prepared under the optimum condition of ultrasonic treatment, and the thermal conductivity of the composite improved proportionally along with the particle size of graphite. When the silicone composite was prepared by using a mixture of inorganic oxides and graphite rather than graphite alone, the thermal conductivity of the silicone composite was further increased. A silicone composite containing graphite was used for LED (light emitting diode) lighting system as a thermal interface material (TIM), and the temperature elevation due to heat generated, while the lighting was actually operated, was analyzed.

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Thermal conductivity of molten salt mixtures: Theoretical model supported by equilibrium molecular dynamics simulations

The Journal of Chemical Physics ◽

10.1063/1.4942197 ◽

2016 ◽

Vol 144 (8) ◽

pp. 084506 ◽

Cited By ~ 14

Author(s):

Aïmen E. Gheribi ◽

Patrice Chartrand

Keyword(s):

Thermal Conductivity ◽

Molecular Dynamics ◽

Theoretical Model ◽

Molecular Dynamics Simulations ◽

Molten Salt ◽

Salt Mixtures ◽

Dynamics Simulations

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Investigation of thermal conductivity of single-wall carbon nanotubes

Thermal Science ◽

10.2298/tsci110225038j ◽

2011 ◽

Vol 15 (2) ◽

pp. 565-570 ◽

Cited By ~ 1

Author(s):

Mahmoud Jafari ◽

Majid Vaezzadeh ◽

Momhamad Mansouri ◽

Abazar Hajnorouzi

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotubes ◽

Theoretical Model ◽

Potential Energy ◽

Experimental Results ◽

Single Wall Carbon Nanotubes ◽

Lattice Vibrations ◽

Single Wall Carbon ◽

Thermal Potential ◽

Conductivity Behavior

In this paper, the thermal conductivity of Single-wall carbon nanotubes (SWCNTs) is determined by lattice vibrations (phonons) and free elections. The thermal conductivity of SWCNTs is modeled up to 8-300 K and the observed deviations in K-T figures of SWCNTs are explained in terms of phonon vibrations models. An suitable theoretical model is shown for thermal conductivity behavior with respect to temperature and is generalized for experimental results. This model enables us to calculate thermal conductivity SWNTs and Thermal Potential Energy (TPE).

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Design and Implementation of a Laboratory Equipment for Studying Heat Transfer by Conduction

Műszaki Tudományos Közlemények ◽

10.33894/mtk-2019.11.34 ◽

2019 ◽

Vol 11 (1) ◽

pp. 153-156

Author(s):

István Padrah ◽

Judit Pásztor ◽

Rudolf Farmos

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Heat Conduction ◽

Thermal Conduction ◽

Transfer Mechanism ◽

Measuring Instrument ◽

Heat Transfer Mechanism ◽

Laboratory Equipment ◽

Insulating Materials ◽

Design And Implementation

Abstract Thermal conduction is a heat transfer mechanism. It is present in our everyday lives. Studying thermal conductivity helps us better understand the phenomenon of heat conduction. The goal of this paper is to measure the thermal conductivity of various materials and compare results with the values provided by the manufacturers. To achieve this we assembled a measuring instrument and performed measurements on heat insulating materials.

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