A solid can serve as a medium for heat and sound wave interactions just like a fluid does for thermoacoustic engines and refrigerators -- resulting in leak-free machines that can stay operating longer، as the ScienceDaily reports.
Researchers envision thermoacoustics in solids eventually harnessing the extreme temperature gradient of outer space for electricity on satellites.
A solid can serve as a medium for heat and sound wave interactions just like a fluid does for thermoacoustic engines and refrigerators -- resulting in leak-free machines that can stay operating longer.
Leaky systems have limited how engineers design thermoacoustic devices that rely on the interplay between temperature oscillations and sound waves. Researchers at Purdue and the University of Notre Dame have demonstrated for the first time that thermoacoustics could theoretically occur in solids as well as fluids، recently presenting their findings at the 175th Meeting of the Acoustical Society of America.
"Although still in its infancy، this technology could be particularly effective in harsh environments، such as outer space، where strong temperature variations are freely available and when system failures would endanger the overall mission،" said Fabio Semperlotti، Purdue assistant professor of mechanical engineering.
Thermoacoustics has been an established and well-studied phenomenon in fluids -- whether as a gas or liquid -- for centuries. "Applying heat to a fluid enclosed in a duct or cavity will cause the spontaneous generation of sound waves propagating in the fluid itself،" said Carlo Scalo، an assistant professor of mechanical engineering at Purdue. "This results in so-called singing pipes، or thermoacoustics machines."
While fluids have been historically used for these systems، the extra step of building something to contain the fluids and prevent leaks is cumbersome. This led the researchers to consider solids as a replacement.
"Properties of solids are more controllable، which could make them potentially better suited to these applications than fluids. We needed to first verify that this phenomenon could theoretically exist in solid media،" said Haitian Hao، Purdue graduate research assistant in mechanical engineering