Influence of phase of standing wave on suppression of soot from acetylene diffusion flame

This work focuses on the investigation of the influence of the relative position of the standing wave on the suppression of soot from the acetylene diffusion flame. The initial phase of the one-sided speaker was changed to adjust the standing wave in the waveguide. The results show that the flame has better soot suppression efficiency at the pressure node than at the pressure anti-node for the same frequency and amplitude. The acoustic kinetic energy and particle velocity at the pressure node are larger than those at the pressure antinode. Moreover, the soot suppression efficiency increases with the increase of the acoustic kinetic energy and particle velocity at the same frequency. When the phase differences of the two speakers are between 90° and 270°, obvious change of flame shape (i.e., circumferential, area, height) and combustion efficiency were observed in comparison with that when there is no phase difference. The time evolution of the flame front suggests that the flame fluctuated differently at different standing wave positions. And the characteristics of the flame front and the increase in flame temperature indicate that the enhancement in combustion efficiency and more oxidation of soot when there is phase difference.