caa a22 4500 46575578X CHVBK 20180323111846.0 cr unu---uuuuu 170327e19900901xx s 000 0 eng 10.1007/BF00503584 doi (NATIONALLICENCE)springer-10.1007/BF00503584 De Coninck R. Materials Development Department, SCK/CEN, B-2400, Mol, Belgium aut On the analysis of the thermal diffusivity measurement method with modulated heat input [Elektronische Daten] [R. De Coninck] The present paper proposes a simplified way to analyze thermal diffusivity experiments in which the phase shift is measured between the modulations of the temperatures on either face of a disk-shaped sample. The direct application of complex numbers mathematics avoids the use of the cumbersome formulae which hitherto have hampered a wider confirmation of the method and which restricted the range of the phase lag to an angle of 180°. The algorithm exposed makes it more practical to refine the analysis, which may lead to a higher accuracy and a wider use of the method. The origins of some possible errors in the calculated results are briefly reviewed. Plenum Publishing Corporation, 1990 Complex numbers analysis nationallicence modulated heat input nationallicence phase shift nationallicence measurement nationallicence thermal conductivity nationallicence thermal diffusivity nationallicence a : Thermal diffusivity, m2 · s−1 nationallicence c : Index denoting a constant part, dimensionless nationallicence c l, c 0 : Inverse extrapolation length, m−1 nationallicence C p : Specific heat, J · kg−1 · K−1 nationallicence f : Modulation frequency, Hz nationallicence l : Thickness of disk-shaped sample, m nationallicence Q c : Equilibrium energy per unit surface deposited on surface x=l, W · m−2 nationallicence Q m( t ) : Energy of modulation per unit surface deposited on surface x=l, W · m−2 nationallicence Q(t) : Total energy per unit surface deposited on surface x=l, W · m−2 nationallicence q : Complex energy modulation amplitude, W · m−2 nationallicence T l : Equilibrium temperature of heated surface, K nationallicence t 0 : Equilibrium temperature of nonheated surface, K nationallicence T(x, t) : Total temperature of any plane at distance x and at time t, K nationallicence T m( x, t ) : Modulation temperature at any distance x and at time t, K nationallicence t : Time, s nationallicence x : Distance perpendicular to the specimen's surface and with the nonheated surface as the reference, m nationallicence α : Thermal linear expansion coefficient, dimensionless nationallicence β : Intermediary parameter, m−2 nationallicence Δ : Phase difference between heated and nonheated specimen face, radian nationallicence δ 0 : Phase difference between energy modulation and nonheated face, radian nationallicence δ l : Phase difference between energy modulation and heated face, radian nationallicence ɛ : Total emissivity, dimensionless nationallicence ɛ s : Spectral emissivity, dimensionless nationallicence θ : Temperature, amplitude of modulated part argument, K nationallicence λ : Thermal conductivity, W · m−1 · K−1 nationallicence ρ : Density, kg · m−3 nationallicence σ : Stefan-Boltzmann constant, 5.66961×10−8W · m−2 · K−4 nationallicence ω : Angular frequency=2πf, s−1 nationallicence International Journal of Thermophysics Kluwer Academic Publishers-Plenum Publishers 11/5(1990-09-01), 923-935 0195-928X 11:5<923 1990 11 10765 https://doi.org/10.1007/BF00503584 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00503584 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- De Coninck R. Materials Development Department, SCK/CEN, B-2400, Mol, Belgium aut NATIONALLICENCE 773 0- International Journal of Thermophysics Kluwer Academic Publishers-Plenum Publishers 11/5(1990-09-01), 923-935 0195-928X 11:5<923 1990 11 10765 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer