Photothermal Gas Analyzer for Simultaneous Measurements of Thermal Diffusivity and Thermal Effusivity

Abstract

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.

Measuring Nanofluid Thermal Diffusivity and Thermal Effusivity: The Reliability of the Photopyroelectric Technique

“…Esquef et al [36], in 2006, developed a method consisting essentially of a photoacoustic cell and a PE cell enclosed in a single compact gas analyzer for the measurement of thermal diffusivity and thermal effusivity. Concerning the front configuration, a simplified method to measure both the thermal diffusivity and thermal effusivity of sensor was proposed.…”

“…Their thermal diffusivity and effusivity measurements were obtained with high accuracy (within 0.5%), and the results were sensitive to changes in the relevant parameters of the nanofluid as the base fluid, concentration and type of NPs. Thus, the front PPE method [13][14][15][35][36][37][38][39] was a suitable for accurate and simultaneous measurements of thermal diffusivity and effusivity of nanofluids.…”