Gas-Filled Encapsulated Thermal-Acoustic Transducer

Abstract

A new model for a gas-filled encapsulated thermal-acoustic transducer, which uses newly devised carbon nanotube (CNT) thin film is developed and the exact and approximate solutions are derived. A comparison between theoretical prediction and experimental data is presented and excellent agreement is reported. The frequency response for this acoustic transducer is investigated and the acoustic response of as a function of window–thin-film distance of the encapsulated transducer is discussed. An optimal distance between window and thin film is successfully derived and used in some practical examples. Resonance takes place for a suitable input frequency, and thus such transducers can be used to either generate acoustic waves of specific frequency or to filter specific resonant frequencies from a wide spectrum of signals. This kind of transducer can be immersed in different liquid media. A gaseous medium shows better performance at lower frequency while it is otherwise for a liquid medium. The conclusions derived in this work could be regarded as effective guidelines and information for enhancing thermal-acoustics efficiency conversion, as well as for the optimal design of a thermal-acoustic transducer.

Experimental characterization of three-dimensional Graphene’s thermoacoustic response and its theoretical modelling

“…Since carbon nanostructured materials possess the thermal properties required [7], extensive research has been conducted on their potential to emit sound via the thermoacoustic effect, such as carbon nanotubes (CNTs) [6][7][8][9][10][11][12][13][14][15][16][17][18][19], 2D graphene [20][21][22][23][24][25], and 3D graphene (3D-C) [26,27]. These studies demonstrate the influence of frequency, input power, microstructure and backing on the acoustics performance of the carbon nanostructured materials, obtained from the conducted experiments.…”

Thermoacoustic wave generation in multilayered thermophones with cylindrical and spherical geometries

“…39,40 This continuity is automatically verified if we adopt the matrix form given in Eq. (42). By imposing the continuity of the variables at interfaces between layers we found…”

Gap separation effect on thermoacoustic wave generation by heated suspended CNT nano-thinfilm

“…Here subscript 2 indicates parameters that are related to the substrate. The thermal diffusion length of thermal wave is ffiffiffiffiffiffiffiffiffiffiffiffiffiffi 2a 2 =u p [4,21,22,25], hence thermally-thick condition is readily satisfied for the substrate. By using no reflection boundary condition, the thermal wave sharply attenuates before arriving at the back of substrate.…”

“…However, the influence of thermal loss and conductor HCPUA was not included in their analysis [13]. Recently, Lim et al [6] and Tong et al [22] reported accurate analytical solutions for thermoacoustic radiation from a suspended (CNT) thinfilm and a gas-filled encapsulated thermoacoustic transducer, respectively. Their analytical solutions were compared with published experimental measurements and excellent agreements were achieved.…”