Measurement of the thermal diffusivity by the laser-flash method with repeated pulses
Libor Vozár, Wolfgang Hohenauer
The measurement of thermal diffusivity by the laser-flash method with repeated pulses is examined. The aim of the proposed experimental method is to present a new approach to overcome particular experimental difficulties associated with the measurement of some types of insulators, temperature-sensitive materials, and large-grain heterogeneous materials by the standard laser-flash method. Unlike the known approaches, based on reducing the energy intensity and simultaneously increasing the exposure time (the flash method with extended pulse), or substituting step (continuous) heating for pulse irradiation (the step-heating method), respectively, in the technique presented the pulse energy consists of several consecutive pulses periodically applied to the sample front face. The thermal diffusivity is calculated from the resulting temperature rise of the rear face, in a similar way to the standard ‘one-pulse’ laser-flash method.