Functionalized Aerogels for Thermoacoustic Emission

• Applicants: Dr.-Ing. Mate Gaal; Professor Dr. Pavel Gurikov
• Subject Area: Chemical and Thermal Process Engineering
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 560281845

Air-coupled ultrasonic transducers have been increasingly applied to enable contact-free ultrasonic testing in several industrial branches. In particular, they are used for testing lightweight components and thus contribute to the reduction of pollutant emissions, technical safety and the circular economy. The current ultrasonic transducers are however very much restricted by the difficulties of overcoming impedance mismatch between air and the piezocomposite. A new generation of ultrasonic transducers could be based on the thermoacoustic effect. Although theoretical estimations show that the thermoacoustic effect can be potentially utilized to create very efficient acoustic transducers, the sound pressure levels of existing prototypes are far away from the commercial ones. In this project, we intend to demonstrate the giant thermoacoustic effect required for creation of high-performance thermoacoustic transmitters. The principal goal lies in developing a new class of aerogel-based substrates with exceptionally low thermal effusivity. To achieve this goal, a toolbox of nano-scaled approaches for tailoring the internal structure, surface morphology and chemistry of aerogels will be developed. These approaches are of general use and can principally be applied to any open porous materials. Practical outcomes of the project would enable testing of thicker components and materials with high acoustic damping. The results would also enable miniaturization of both ultrasonic sources and the electrical matching network, broadening the application area of air-coupled ultrasonic testing.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Vasile-Dan Hodoroaba, Ph.D.