The effects of a finite pulse time in the flash thermal diffusivity method

Abstract

After a brief review of the finite pulse time effects in flash thermal diffusivity measurements, an analytical expression for an exponential shape pulse was determined using the Green function method. The results were compared with those obtained by Larson and Koyama. It was found that, using the Larson and Koyama equation, when the dimensionless time ω is equal to zero, the dimensionless temperature rise V cannot reach zero, and when ω_p, the time characterizing the dimensionless pulse, approaches 1/n ² (n=1,2,3,...), a large error of ω_1/2 will result. These contradictions have been resolved by the present work. In other respects, both sets of results concurred. The results are compared with the triangular pulse and are discussed.