Sonic soot-blowing technology in coal-fired boilers is widespread due to its advantages in strong penetration, a wide range of action, and non-destructiveness. However, improving the acoustic radiation performance of the air-modulated speaker has been a significant challenge that has limited the further development of acoustic soot-blowing technology. In this paper, numerical simulations of the coupled acoustic radiation characteristics of a two-dimensional Conical acoustic wave guide tube with an exponential horn tube are carried out using the finite element method. This study focuses on the relationship between the resonance frequency of the sound source and the structural parameters of the exponential horn. The waveform characteristics of the acoustic signal at the center of the horn exit are systematically investigated. Furthermore, the waveform distortion along the propagation path under different driving frequencies is analyzed in detail. Calculated results show that the resonant frequency decays exponentially with increasing horn length. The frequency corresponding to the first resonance peak of the system initially remains constant with increasing shape parameters and then increases. The frequency corresponding to the second resonance peak of the system decreases with the increase of the shape parameter. When the driving frequency is the resonance frequency of the system, and the length of the horn is greater than 0.8 meters, there will be a waveform instability and the beat vibration phenomenon. The conclusions of the study can provide some theoretical references for the selection of the optimal driving frequency of air-modulated speakers of different structures.
Yang et al. (Sun,) studied this question.