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ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
Synthesis of the transfer matrix of thermoacoustic cores toward an inverse problem
Submission Author:
Denis Gomes , SP
Co-Authors:
Denis Gomes, Flávio Bannwart
Presenter: Denis Gomes
doi://10.26678/ABCM.ENCIT2020.CIT20-0213
Abstract
The performance of thermoacoustic devices, either engines or refrigerators, depends essentially on the design of its main component: the thermoacoustic core (TAC), which comprises a porous material, heat exchangers and a thermal buffer tube. Usual porous materials of the most efficient devices are complex in its internal geometry, which makes convenient its experimental characterization as an implicit component of the entire TAC, to be treated as a black box in the form of a transfer matrix. From this measured data, a particular TAC can then be inserted into a simulated waveguide network so that to constitute a thermoacoustic engine (TAE), whose performance can be analytically predicted from usual transfer matrix relations. Nonetheless, selecting the best porous material for a certain TAE configuration by experimental means is highly time demanding due to the laborious iterative process involved. On the other hand, for complex porous materials, analytical or numerical approaches are so far impractical. The purpose of this work is to explore experimental data from previous works, where TAC acoustic transfer matrices had been measured, aiming to circumvent the need of such iterative experimental process in the quest for a better porous material. Those matrices are adequate and directly edited with close observation of the resulting new simulated - and artificial - performance. They are evaluated with respect to the actual physical system and corresponding boundary conditions by contrasting their values to the real transfer matrix data. The corresponding determinant, which measures the degree of nonreciprocity, is proposed as reference for selecting the synthesized transfer matrices as a preceding step toward the optimal design of porous materials from an inverse problem approach.
Keywords
thermoacoustics, thermoacoustic core, transfer matrix synthesis, Inverse problem, porous material design
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