Photothermal gas analyzer for simultaneous measurements of thermal diffusivity and thermal effusivity.
In this paper, we describe a new, simple, and fast photothermal method for simultaneous measurements of two important gas thermal properties: thermal diffusivity and thermal effusivity. The method consists essentially in combining a photoacoustic cell and a thermal wave pyroelectric cell enclosed in a single compact gas analyzer. The photoacoustic cell is kept filled with synthetic air and sealed. The pyroelectric cell is also filled with synthetic air, and after some warm up time, the synthetic air is exchanged to the gas of interest. It is shown that the analysis of the transient and saturation signals of both photoacoustic and pyroelectric cells is capable of measuring the thermal properties with an accuracy of 3%. This particular capability of performing simultaneously the measurements of thermal diffusivity and thermal effusivity allows us to carry on the complete characterization of the thermal properties of gases.
Esquef
Israel A
IA
Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brazil.
Siqueira
Ana Paula L
AP
da Silva
Marcelo G
MG
Vargas
Helion
H
Miranda
Luiz Carlos M
LC