Focal plane array based infrared thermography in fine physical experiment

Abstract

By two examples of dissimilar physical phenomena causing thermophysical effects, the unique capabilities of one of the up-to-date methods of experimental physics—focal plane array (FPA) based infrared (IR) thermography (IRT), are demonstrated distinctly. Experimenters inexperienced in IRT can grasp how this method provides a means for combining real-time visualization with quantitative analysis. A narrow-band short-wavelength IR camera was used in the experiments. It is discussed and stated that IRT is best matched and suited to the next two test conditions—when a heated specimen is thin and when heat is generated in the immediate region of a surface of a solid. The first prerequisite is realized in the search for directional patterns of combined low-power radiation sources with the use of the IRT-aided method. The second one is realized in studies of water vapour adsorption on uneven (irregular) surfaces of solid materials. With multiple swatches taken from a set of different fabrics and used as experimental samples, a sharp distinction between adsorptivities of their surfaces is strikingly illustrated by IRT time-domain measurements exhibiting the associated thermal effect ranging within an order of magnitude. It is justified that the described IRT-aided test can find practical implementation at least in the light industry. Emissivities of different fabrics are evaluated experimentally with the described reflection method based on the narrow spectral range of IRT. On the basis of direct IR observations, attention is paid to the need for close control over the surface temperature increase while the adsorption isotherms are being measured. Sensitivity of the FPA-based IRT method, as applied to examine the kinetics of initial stages of adsorption of gaseous molecules on the solid surface, is evaluated analytically and quantitatively. The relationship between the amount of adsorbate and the measurable excess of adsorbent temperature is found. It is discovered that the method makes it possible to control nano-quantities of the adsorbed matter, namely, it is sensitive to an incipient molecular film of 1/300-monolayer effective thickness.

Dynamics of thermal and moistening fronts in porous material under capillary moistening

“…The most promising contactless method for studying thermal characteristics of materials is infrared (IR) thermography method [18,19]. In spite of the large number of works employing this method, there are several research areas where it has been used insufficiently actively.…”

Real-time thermal imaging and quantitative characterization of adsorption-desorption processes in zeolites and silica gels

“…It has been theoretically proved [2,3] that extremely high thermal sensitivity of the FPA-based infrared thermography method can be useful for the studies of gas adsorption on solid thin films. By this contribution, we present our experimental results on visualization and quantitative characterization of the thermal processes occurring during the adsorption and desorption of vapors and gases in grains and beds of various solid adsorbents.…”

Infrared thermography and spectrometry realized by the use of indium arsenide multielement CID photodetectors

“…This fact required the great volume of investigations [7,8,[19][20][21][22][23][24][25][26][27]. The investigations were predominantly devoted to exposure of the factors able to influence the results of measurement and practical application of the considered photosensitive cells combined in multielement devices.…”