Solid-State Thermoacoustics

Thermoacoustics is a process of energy conversion between thermal and mechanical energy driven by a thermal gradient. After the initial observation of heat-induced sound in glass-blowing processes, the field of thermoacoustics of fluids has been constantly developing. To-date, several practical applications of the thermoacoustic effect have been explored and led to intriguing devices such as engines and heat pumps. In this study, we expand the theoretical background of thermoacoustics by showing that this fascinating mechanism exists also in solid media. The main characteristics of thermoacoustics of solids will be presented by using a combination of theoretical and numerical continuum models. Despite some commonalities with the traditional thermoacoustics of fluids, some essential and non-trivial differences will be highlighted. The discovery and validation of this physical mechanism in solids may motivate the design of a new generation of ultra-compact and robust solid-state thermoacoustic engineering devices.