A three-stage looped traveling-wave thermoacoustic system with high efficiency thermoacoustic conversion and acoustic power transmission potential is studied through computational fluid dynamics simulation. ωτ, an important dimensionless parameter representing the heat exchange efficiency of the system, is related to the efficiency of sound production and depends on the frequency, hydraulic radius and temperature of the regenerator. The influence of resonance tube radius on the system performance is analyzed, while the acoustic impedance and exergy loss of main components are given. The proposed unequal-radius resonance tubes help with the realization of acoustic power amplification and impedance matching. After parameter evaluation, the proportion of traveling wave in the whole system increases, and the impedance amplitude of some resonance tubes also becomes higher. The mechanism and effect of ωτ on the system performance are expounded. The simulation results show that when the ωτ is 5.7, acoustic power of 8.9 kW and relative Carnot efficiency of 53.1% are obtained, which are higher than the performance of the baseline model.
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