Noninvasive acoustic temperature tomography in multiphase materials

Abstract

Noninvasive thermal characterization of materials undergoing phase transitions is critical for a wide range of industrial applications, including monitoring thermal energy storage systems, lithium batteries, and manufacturing processes. Traditional methods, based on thermocouples and infrared imaging, are limited by their invasive nature and inability to capture subsurface temperature distributions, respectively. In this study, we present the first application of acoustic tomography to map the internal temperature distribution and phase transition. We employed both thin-ray and fat-ray travel-time tomography techniques to reconstruct the thermal gradients of phase transitioning material (PTM) inside the closed container. We observed good agreement between temperatures from acoustic thermal tomography versus thermocouples, with average errors between 5 °C–8 °C for fat ray and thin ray tomography. This noninvasive method successfully captured both the solid and liquid phases of PTM, highlighting its potential for monitoring phase transitions in other materials with complex thermal behaviors. The results of this study demonstrate that acoustic tomography, particularly fat-ray tomography, is a reliable and precise method for noninvasive temperature monitoring in phase-change systems and processes, opening up new possibilities for real-time monitoring of hazardous, sensitive, or otherwise inaccessible materials.