Uncertainty of Thermal Diffusivity Measurements Using the Laser Flash Method

Vozár, Libor; Hohenauer, Wolfgang

doi:10.1007/s10765-005-8604-5

Cited by 50 publications

(26 citation statements)

References 13 publications

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“…This paper uses LFA 37,38 to quantify the temperature dependence individually for D ele and D lat for diverse metals at ordinary temperatures, independent of any formulations suggested by mechanistic models. Low T behavior likely differs, but is not addressed here.…”

Section: Purpose Of the Present Studymentioning

confidence: 99%

“…The signal is analyzed using a slight modification of Parker et al's 37 original adiabatic model. 38,39 Signal properties suggest an electronic mechanism. From our measurements of D ele (Sec.…”

Section: Purpose Of the Present Studymentioning

confidence: 99%

“…The temperature dependence of D is then determined solely by varying furnace temperature. [37][38][39]53 Heat capacity can be determined from ∆T using additional information on Q. But because the efficiency of energy absorption affects Q, this determination assumes only one carrier exists.…”

Section: 53mentioning

confidence: 99%

“…38 Thus, the raw data are referred to as a T -t curve. Its shape determines the thermal diffusivity in accordance with Eq.…”

mentioning

confidence: 99%

“…Furthermore, baseline corrections remove effects of stray light and background radiation from hot components. Requirements are straightforward [37][38][39]53 : It is important to have parallel faces, to avoid strong temperature gradients across the sample, and for the pulse to be absorbed by a thin coating (Fig. 5).…”

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confidence: 99%

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Isolating lattice from electronic contributions in thermal transport measurements of metals and alloys above ambient temperature and an adiabatic model

Criss

Hofmeister²

2017

Int. J. Mod. Phys. B

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From femtosecond spectroscopy (fs-spectroscopy) of metals, electrons and phonons reequilibrate nearly independently, which contrasts with models of heat transfer at ordinary temperatures (T > 100 K). These electronic transfer models only agree with thermal conductivity (k) data at a single temperature, but do not agree with thermal diffusivity (D) data. To address the discrepancies, which are important to problems in solid state physics, we separately measured electronic (ele) and phononic (lat) components of D in many metals and alloys over ∼290-1100 K by varying measurement duration and sample length in laser-flash experiments. These mechanisms produce distinct diffusive responses in temperature versus time acquisitions because carrier speeds (u) and heat capacities (C) differ greatly. Electronic transport of heat only operates for a brief time after heat is applied because u is high. High D ele is associated with moderate T , long lengths, low electrical resistivity, and loss of ferromagnetism. Relationships of D ele and D lat with physical properties support our assignments. Although k ele reaches ∼20 × k lat near 470 K, it is transient. Combining previous data on u with each D This is an Open Access article published by World Scientific Publishing Company. It is distributed under the terms of the https://creativecommons.org/licenses/by/4.0Creative Commons Attribution 4.0 (CC-BY) License. Further distribution of this work is permitted, provided the original work is properly cited. * E. M. Criss is an employee of Panasonic Avionics Corporation, but prepared this paper independent of his employment and without use of information, resources, or other support from Panasonic Avionics Corporation.† Corresponding author. provides mean free paths and lifetimes that are consistent with ∼298 K fs-spectroscopy, and new values at high T . Our findings are consistent with nearly-free electrons absorbing and transmitting a small fraction of the incoming heat, whereas phonons absorb and transmit the majority. We model time-dependent, parallel heat transfer under adiabatic conditions which is one-dimensional in solids, as required by thermodynamic law. For noninteracting mechanisms, k ∼ = ΣC i k i ΣC i /(ΣC 2 i ). For metals, this reduces to k = k lat above ∼20 K, consistent with our measurements, and shows that Meissner's equation (k ∼ = k lat + k ele ) is invalid above ∼20 K. For one mechanism with multiple, interacting carriers, k ∼ = ΣC i k i /(ΣC i ). Thus, certain dynamic behaviors of electrons and phonons in metals have been misunderstood. Implications for theoretical models and technological advancements are briefly discussed.

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Section: Purpose Of the Present Studymentioning

confidence: 99%

Section: Purpose Of the Present Studymentioning

confidence: 99%

Section: 53mentioning

confidence: 99%

“…38 Thus, the raw data are referred to as a T -t curve. Its shape determines the thermal diffusivity in accordance with Eq.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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Isolating lattice from electronic contributions in thermal transport measurements of metals and alloys above ambient temperature and an adiabatic model

Criss

Hofmeister²

2017

Int. J. Mod. Phys. B

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Uncertainty Quantification in Modeling Mold Heat Transfer in Steel Continuous Slab Casting with CON1D

Wells,

Thomas

2024

steel research int.

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Computational models are powerful tools to quantify physical phenomena to gain valuable insights into a manufacturing process. Their accuracy is hindered, however, by uncertainty in the input data. Furthermore, when calibrating models with plant measurements, it helps to understand which variables have greatest effect on the critical model outputs. This work applies uncertainty quantification and sensitivity analysis to determine the most influential input parameters in the CON1D model of heat transfer and solidification in steel continuous casting with slag. Results show that the slag rim greatly affects heat flux near the meniscus, so control of its size is important. Heat flux and temperature down the mold depend greatly on velocity of the solid slag layer, and slag solidification temperature, which control the slag layer thickness, which in turn affects the interfacial resistance that controls heat transfer in the process. Scale formation on the mold coldface greatly increases mold temperatures. Based on the results presented here, models of heat transfer in continuous casting such as CON1D would benefit from plant measurements such as slag rim size and solid slag velocity, and lab measurements such as slag viscosity at lower temperatures, to better characterize this important slag property.

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A Review on Sources of Uncertainty in Thermal Conductivity Measurement for Thermal Transport Metrology

Kumar

Misra

Bano

et al. 2022

Recent Advances in Metrology

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Uncertainty of Thermal Diffusivity Measurements Using the Laser Flash Method

Cited by 50 publications

References 13 publications

Isolating lattice from electronic contributions in thermal transport measurements of metals and alloys above ambient temperature and an adiabatic model

Isolating lattice from electronic contributions in thermal transport measurements of metals and alloys above ambient temperature and an adiabatic model

Uncertainty Quantification in Modeling Mold Heat Transfer in Steel Continuous Slab Casting with CON1D

A Review on Sources of Uncertainty in Thermal Conductivity Measurement for Thermal Transport Metrology

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