Infrared visualization of lumped and non-lumped thermal transient processes in an introductory laboratory

The time dependence of the temperature distribution in cooling/heating bodies is studied with a simple, direct visual measurement of infrared radiation. The adoption of a smartphone thermal camera allows one to verify some essential features of theoretical models which describe the temperature field in a cylindrical symmetric configuration for both lumped (concentrated) and non-lumped (distributed) behaviors. Theoretical results and experimental temperature fields acquired via infrared thermal analysis of cooling solid cylinders compare well. The approach can be adopted to support an introductory route to the study of these classes of processes at very low cost and with a fast and simple laboratory procedure. This scheme is appropriate for undergraduate engineering and physics students. (paper)