Ultra-broadband metamaterial silencer with outstanding heat-transferring performance

It is desired to achieve broadband noise reduction while supporting heat and fluids transmission simultaneously. However, attenuating sound energy with simultaneously achieving excellent heat-transferring performance in a fluid environment has yet to be explored. Here, we demonstrate an ultra-broadband absorber with outstanding thermal convection under a fluid environment, whose thickness is only λ/15 (λ is the airborne wavelength). By linearly extending the embedded apertures, the silencer can achieve sound absorption in the range of 455-585 Hz and can block more than 90% of sound energy in the ultra-broadband range of 455-1600 Hz. In addition, the outstanding thermal convection performance of the metamaterial absorber is experimentally demonstrated.