Advanced measurements with contact in heat transfer: principles, implementation and pitfalls
Résumé
The main objective of this lecture is to make the end users aware of the various physical phenomena and especially of the errors frequently met during temperature and heat flow measurement. The lecture is divided in two main parts dealing with thermal measurement at macroscale and micro and nanoscales respectively. In Part 1, phenomena which occur in thermometry with contact (thermoelectric effects, thermoresistance) will be presented. For thermometry with contact, the analysis of systematic errors related to the local disturbance of field temperature due to the introduction of sensors will be emphasized. Indeed intrusive effects due to sensors are usually ignored and can be reduced using know how as will be shown through analytical modeling. Otherwise, interests of using semi intrinsic thermocouples will be discussed. The specificities of temperature measurement in fluid flow will be detailed. Finally heat flow measurement using direct methods (gradient, enthalpic, electric dissipation ...) or inverse methods (heat flow sensors with network of thermocouples) will be reminded. Part 2 focuses on fundamentals of Scanning Thermal Microscopy (SThM) methods. After a description of the main Scanning Probe Microscopy-based techniques developed for thermal imaging with a nanoscale spatial resolution, the approaches currently used for calibrating the SThM probes are given. In many cases, the link of the nominal measured signal to the research parameter is not yet fully established due to the complexity of the micro-/nanoscale interaction between the probe and the sample. Special attention is given to this micro/nanoscale interaction that conditions the tip-sample interface temperature, which is critical for many applications.
Domaines
Thermique [physics.class-ph]Origine | Fichiers produits par l'(les) auteur(s) |
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