Retrieving the thermal diffusivity and effusivity of solids from the same frequency scan using the front photopyroelectric technique
View/ Open
Date
2017-09-14Author
Oleaga Páramo, Alberto
Apiñaniz Fernández de Larrinoa, Estibaliz
Metadata
Show full item record
Measurement Science and Technology 28(10) : (2017) // Article ID 105011
Abstract
The photopyroelectric (PPE) technique in the front configuration consists in illuminating one
surface of a pyroelectric slab while the other surface is in contact with the test sample. This
method has been widely used to measure the thermal effusivity of liquids. Recently, it has
been extended to measure the thermal effusivity of solids, by taking into account the influence
of the coupling fluid layer used to guarantee the thermal contact. In both cases, the sample
(liquid or solid) must be very thick. In this work, we propose a classical frequency scan of a
thin sample slab to retrieve the thermal diffusivity and effusivity simultaneously. We use the
amplitude and the phase of the front PPE signal, which depend on four parameters: the sample
diffusivity and effusivity, the coupling fluid thickness and the coefficient of heat losses. It is
demonstrated that the four quantities are not correlated. PPE measurements performed on a
set of calibrated solids confirm the ability of the method to obtain the thermal diffusivity and
effusivity of solids accurately.