Measurement of thermal diffusivity of isotropic materials using a laser flash method and its validation by finite element analysis

Two experimental arrangements have been used to measure the thermal diffusivity at room temperature using laser pulse healing. One uses circular disc specimens and the other rectangular plate-like specimens to measure both one-dimensional and three-dimensional heat transfer. In both experimental configurations a pulsed laser beam which has a circular cross section is irradiated onto the front surface of the specimen. The time dependence of the temperature response of a circular area on the back surface of the specimen is measured using a radiation detector. The experimental data is then used to calculate thermal diffusivity using appropriate analytical expressions. The theory of these methods is outlined and results are discussed. In addition, finite element models have been generated for one-dimensional and two-dimensional transient thermal analysis of the specimens. These results are shown to be in close agreement with the results of experiments within the bounds of experimental error, hence, validating the experimental measurements.