Robust determination of thermal diffusivity values from periodic heating data

Perez, Laetitia; Autrique, Laurent

doi:10.1088/0266-5611/25/4/045011

Cited by 10 publications

(9 citation statements)

References 15 publications

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“…It was shown that the use of the dual-phase-lag heat conduction model is necessary when the metal film thickness is of order and the angular frequency of the signals is of order 10 −6 m and the angular frequency of the signals is of order 10 12 rad·s −1 . Perez and Autrique [10] investigated an experimental technique dedicated to thermal diffusivity or thermal conductivity identification in isotropic and orthotropic materials. The method is based on analysis of thermal waves induced by periodic excitation in planar samples.…”

Section: Introductionmentioning

confidence: 99%

A Three-Layers Plane Wall Exposed to Oscillating Temperatures with Different Amplitudes and Frequencies

Sadik¹

2018

EPE

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A linear model of three layers plane wall exposed to oscillating temperatures with different amplitudes and frequencies was built by using a physical superposition. A physical superposition of two states was performed, one state is a wall which one surface is exposed to oscillating temperature and the other surface is exposed to zero relative temperature and a second state is a wall which one surface is exposed to relative zero temperature while the other surface is exposed to oscillating temperature with different amplitudes and frequencies. Temperature distributions were introduced for different amplitudes, frequencies and thermal conductivities. It was shown that increasing the frequency value decreases the temperature penetration length, high frequency value leads to extremum temperature values changes on the surface while low frequency value allows gradually temperature changes during the time period. Temperature distribution lines where there are at the same time heat flux entry and heat flux exit were not received for the same constraint frequencies. Energy and Power Engineering appear causing a matter failure. Racopoulos et al. [1] [2] investigated the temperature oscillations in the combustion chamber walls of a diesel engine. Based on theoretical model and experimental measurements, the penetration of the oscillating temperature part of the temperature full value into the inner cylinder wall was shown for few matters. It was observed that when increasing the degree of insulation, the wall temperature swings highly increase, while at the same time the corresponding depth inside which they disappear, decreases. Investigation of the efficiency of a thermoelectric power generator (TPG) was performed by Yan and Malen [3]. Thermoelectric power generator converts heat directly into electricity without moving parts. It was shown that the use of a periodic heat source can increase the efficiency of a TPG. Temperature oscillations may be also formed by a periodic heating. Two methods of periodic heating implementation are an induction heating and a direct resistance heating. Surface hardening, welding and melting are some applications of induction heating. Direct resistance heating has major metal working applications as heating prior to forming and heat treating. Major nonmetals application is a glass melting. Sahin and Yilbas [4] analyzed the temperature rise in an insulated slab which is subjected to a direct resistance heating and to a conduction heating. It was found that for both heating methods, the thermal penetration depth for high frequencies is small.Additional area related to temperature oscillations is the controlling temperature in buildings. Ma and Wang [5] investigated the dynamic heat transfer performance of an exterior Planar Thermal Mass (ePTM) subject to sinusoidal heating and cooling. Analytical solution was performed when the mean value of outdoor air temperature was equal to indoor air temperature. The analytical solution showed that the time lag and the decrement factor are independent of ...

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Section: Introductionmentioning

confidence: 99%

A Three-Layers Plane Wall Exposed to Oscillating Temperatures with Different Amplitudes and Frequencies

Sadik¹

2018

EPE

View full text Add to dashboard Cite

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“…Finally, thermal diffusivity is a key parameter considering the thermal wave propagation. The same considerations can be made for orthotropic materials [5].…”

Section: Effect Of Nuisance Parametersmentioning

confidence: 92%

“…n is the unit normal vector of ∂Ω and h is the convective heat transfer coefficient Introducing the notion of complex temperature (illustrated for example in [5][6][7]), a new system of PDE is considered:…”

Section: Equationsmentioning

confidence: 99%

“…For the first one a conductive isotropic material is investigated while for the second one an orthotropic material (carbon fibres embedded in epoxy resin) is considered. Heating source spatial distribution on the excited face is assumed to be a disk of 5 mm radius and a power of 5 In Figure 2, considering an isotropic material sample (titanium) and a 0.1 Hz excitation frequency (10s period), an amplitude of 40K is obtained in the sample centre.…”

Section: Numerical Simulationsmentioning

confidence: 99%

“…In the literature, various implementations of this approach (called modulated photothermy) can be found for parametric identification. Indeed in [5] this method is used to identify thermal conductivity tensor of orthotropic materials; in [6] identification of thermal diffusivity of fibre embedded in matrix is investigated, and in [7] numerous experimental devices related to the periodic method are presented (allowing investigations from micrometer scale to decimetre scale). Although the key parameter conditioning the thermal wave propagation is the material thermal diffusivity, the use of periodic method to detect defect appears particularly attractive by avoiding the considered material deterioration.…”

Section: Introductionmentioning

confidence: 99%

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