Abstract
A conceptually new approach is proposed to estimate the thermal diffusivity of optically transparent solids at ambient temperature based on the ‘position-dependent instantaneous velocity’ of isothermal surfaces using a self-reference interferometer. A new analytical model is proposed using the exact solution to relate the instantaneous velocity of isothermal surfaces with the thermal diffusivity of solids. The experiment involves setting up a one-dimensional non-stationary heat flow inside the solid via step-temperature excitation to launch a spectrum of dissimilar ‘moving isothermal surfaces’ at the origin. Moving isothermal surfaces exhibit macroscale ‘rectilinear translatory motion’; the instantaneous velocity of any isothermal surface at any location in the heat-affected region is unique and governed by the thermal diffusivity of the solids. The intensity pattern produced by the self-reference interferometer encodes the moving isothermal surfaces into the corresponding moving intensity points. The instantaneous velocities of the intensity points are measured. For a given thermo-optic coefficient, the corresponding values of the isothermal surfaces are predicted to estimate the thermal diffusivity of the solids using BK7 glass as an example. Another improved method is proposed in which thermal diffusivity is estimated without measuring thermo-optic coefficient and quartz glass is utilized as a specimen. The results obtained using the proposed approaches closely match with the literature value.
Similar content being viewed by others
References
E Marin, Eur. J. Phys. 28, 429 (2007)
H S Carslaw and J C Jaeger, Conduction of heat in solids, 2nd edn (Oxford University Press, 1959)
R W King, Phys. Rev. 6, 437 (1915)
Settu Balachandar, N C Shivaprakash and L Kameswara Rao, Proc. SPIE 9524, icOPEN (2015), 95241Q; DOI:10.1117/12.2189532 10.1117/12.2189532
Settu Balachandar, N C Shivaprakash, and L Kameswara Rao, Meas. Sci. Technol. 27, 015201 (2016) DOI:10.1088/ 0957-0233/27/1/015201
A Einstein, Investigations on the theory of the Brownian movement (Dover Publication, New York, 1956)
P Debye, Ann. Phys. 39, 789 (1912)
W J Parker et al, J. Appl. Phys. 32(9), 1679 (1961)
J P Gordon et al, J. Appl. Phys. 36(1), 3 (1965)
S E Gustafsson et al, J. Phys. Chem. 69(3), 1016 (1965)
Siles E Gustafsson, Ernest Karawacki, and Abbas J Hamdani, J. Phys. E: Sci. Instrum. 12, 387 (1979)
E Corona-organiche, Mod. Phys. Lett. B 15(17–19), 613 (2001)
A Rosencwaig and A Gersho, J. Appl. Phys. 47, 64 (1976)
P K Kuo, M J Lin, L D Favro, R L Thomas, D S Kim, Shu-yi-Zhang, L J Inglehart, D Fournier, A C Boccara, and N Yacoubi, Can. J. Phys. 64, 1165 (1986)
A Mandelis, J. Therm. Anal. 37, 1065 (1991)
S De Nicola et al, Opt. Commun. 159, 203 (1999)
L Kubicar, V Vretenar, and U Hammerschmidt, Int. J. Thermophys. 26, 507 (2005)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
BALACHANDAR, S., SHIVAPRAKASH, N.C. & RAO, L.K. Estimation of the thermal diffusivity of solids based on ‘instantaneous velocimetry’ using an interferometer. Pramana - J Phys 88, 41 (2017). https://doi.org/10.1007/s12043-016-1349-9
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/s12043-016-1349-9
Keywords
- Self-reference interferometer
- BK7 glass
- quartz glass
- Fourier heat diffusion
- thermal diffusivity; step-temperature excitation
- instantaneous velocity
- isothermal surface.