Thermal diffusivity of anisotropic materials by photothermal methods

1996 ◽  
Vol 79 (8) ◽  
pp. 3984 ◽  
Author(s):  
A. Salazar ◽  
A. Sánchez-Lavega ◽  
A. Ocáriz ◽  
J. Guitonny ◽  
G. C. Pandey ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Anisotropic Materials ◽  
Photothermal Methods

Novel results on thermal diffusivity measurements on anisotropic materials using photothermal methods

1995 ◽  
Vol 67 (5) ◽  
pp. 626-628 ◽  
Author(s):  
A. Salazar ◽  
A. Sánchez‐Lavega ◽  
A. Ocáriz ◽  
J. Guitonny ◽  
J. C. Pandey ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Anisotropic Materials ◽  
Diffusivity Measurements ◽  
Photothermal Methods

Absorption losses and thermal diffusivity of optical fibers investigated by photothermal methods: theory and experiments

1983 ◽  
Vol 61 (9) ◽  
pp. 1334-1346 ◽  
Author(s):  
Dominique Chardon ◽  
Serge J. Huard
Keyword(s):  
Thermal Diffusivity ◽  
Absorption Coefficient ◽  
Optical Fibers ◽  
Rayleigh Scattering ◽  
Modulation Frequency ◽  
Threshold Value ◽  
Phase Delay ◽  
Algebraic Expression ◽  
Photothermal Methods ◽  
Scattering Losses

Both the absorption coefficient and the thermal diffusivity of an optical fiber have been measured using photothermal methods: photoacoustics (P.A.) and photothermal deflection (P.D.). The amplitude of the photothermal signal is proportional to the heat density generated in the fiber core. This in turn is proportional to the light absorption coefficient β. Thus, these techniques allow one to separate the absorption and Rayleigh scattering losses. The results obtained by the two methods are in agreement. A threshold value of 10 dB km−1 mW has been determined experimentally. In both cases, the device is calibrated by replacing the fiber with a heated electric wire. Moreover, the heat must diffuse from the core to the gas so that when the light is modulated, a phase delay appears. A study of phase delay versus modulation frequency gives the thermal diffusivity of the fiber. This is required in order to improve fiber sensors.Theoretically, the cylindrical geometry of the sample permits simple calculations. The thermoelastic equations in solids and coupled thermodynamic ones in the gas have been solved without neglecting viscosity effects. Noting that silica is almost unexpansible, an algebraic expression of the signal has been obtained without any assumptions on the gas transformation processes. Finally, the P.A. and P.D. techniques are compared and some extensions are presented.

Photothermal methods for determination of thermal properties of bulk materials and thin films

Open Physics ◽  
2010 ◽  
Vol 8 (2) ◽  
Author(s):  
Jerzy Bodzenta ◽  
Anna Kaźmierczak-Bałata ◽  
Jacek Mazur
Keyword(s):  
Thin Films ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Heat Transport ◽  
Temperature Fields ◽  
Nonstationary Temperature ◽  
Measuring Techniques ◽  
Heat Transport Properties ◽  
Photothermal Methods

AbstractInformation on the thermal properties of materials is very important both in fundamental physical research and in engineering applications. The development of materials with desirable heat transport properties requires methods for their experimental determination. In this paper basic concepts of the measurement of parameters describing the heat transport in solids are discussed. Attention is paid to methods utilizing nonstationary temperature fields, especially to photothermal methods in which the temperature disturbance in the investigated sample is generated through light absorption. Exemplary photothermal measuring techniques, which can be realized using common experimental equipment, are described in detail. It is shown that using these techniques it is possible to determine the thermal diffusivity of bulk transparent samples, opaque and semi-transparent plate-form samples, and the thermal conductivity of thin films deposited on thick substrates. Results of the investigation of thermal diffusivity of the ground in the polar region, which is based on the analysis of the propagation of the thermal wave generated by sun-light, are also presented. Based on chosen examples one can state that photothermal techniques can be used for determination of the thermal properties of very different materials.

Thermal diffusivity measurements in porous ceramics by photothermal methods

1997 ◽  
Vol 65 (1) ◽  
pp. 15-22 ◽  
Author(s):  
A. Sánchez-Lavega ◽  
A. Salazar ◽  
A. Ocariz ◽  
L. Pottier ◽  
E. Gomez ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Porous Ceramics ◽  
Diffusivity Measurements ◽  
Photothermal Methods

scholarly journals Constant Velocity Flying Spot for the estimation of in-plane thermal diffusivity on anisotropic materials

2019 ◽  
Vol 145 ◽  
pp. 106000 ◽  
Author(s):  
L. Gaverina ◽  
M. Bensalem ◽  
A. Bedoya ◽  
J. González ◽  
A. Sommier ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Constant Velocity ◽  
Anisotropic Materials ◽  
Flying Spot
Sign in / Sign up

Export Citation Format

Share Document