S. Perananthan, N.K. Mayo, A.E. Aliev
University of Texas at Dallas,
Keywords: thermoacoustics, sound, nanofibers, graphene sponge, heat transfer
Summary:Thermophones are highly promising for such applications as high power sonar arrays, flexible loudspeakers, and noise cancellation devices. So far, freestanding carbon nanotube aerogel sheets provide the most attractive performance as a thermoacoustic heat source. However, the limited accessibility of large-size freestanding carbon nanotube aerogel sheets, and other even more exotic materials recently investigated, hampers the field. We here describe alternative materials for a thermoacoustic heat source with high energy conversion efficiency, additional functionalities, environmentally friendly and cost effective production technologies. We discuss the thermoacoustic performance of alternative nanostructured materials such a sheet of carbonized poly(acrylonitrile) nanofibers and graphene sponge, and compare their spectral and power dependencies of sound pressure in air. We demonstrate that the heat capacity of aerogel-like freestanding nanostructures can be extracted by a thorough analysis of the sound pressure spectra and detection of infrared radiation from the surface of nanofibers. Applications of thermoacoustic projectors for high power SONAR arrays, sound cancellation, and optimal thermal design, regarding enhanced energy conversion efficiency, are discussed.