Springer Online Journal Archives 1860-2000
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Abstract For the measurement of the thermal capacity and the thermal conductivity of films, the thermal excitation of the sample is commonly performed by the absorption of light. This results in a spatial and temporal temperature distribution within the film. With a variety of methods static or dynamic temperature recordings are performed. Two problems with these methods are discussed, the calculation of the temperature distribution in the film and the measurement of the mean surface temperature of the film. An analytical solution of the heat conduction problem for a cylindrical geometry with any radial distribution of the absorbed light is given. Resistive bolometers are introduced for the measurement of the mean surface temperature of the film within a circular area. Experiments with a 25 μm thick PVDF film give excellent agreement with the theoretical calculations within the modulation frequency range 10−3 Hz to 103 Hz, thus allowing a determination of various thermal parameters of the investigated film.
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