Research on non-intrusive particle size measurement method based on acoustic emission technology

In order to overcome the interference of the waveguide on the flow field in the pipe and its own wear, a novel non-intrusive particle size measurement method is proposed by fusing an acoustic emission sensor and an interdigital-type electrostatic sensor. Firstly, based on the theoretical model of Hertz collision, the mathematical model between particle size and particle velocity, as well as the acoustic emission frequency, is established through theoretical analysis. To address the challenge of obtaining the vertical impact velocity of particles against the pipe wall, a method combining spatial filtering and cross-correlation is introduced to acquire the vertical impact velocity. Then RIME-VMD-FastICA algorithm is proposed for denoising the raw acoustic emission signal. Finally, a pneumatic conveying system is set up, and experiments are conducted on quartz sand particles with five sizes of 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, and 1.2 mm. By analyzing the influence of the spatial filtering velocity, the cross-correlation velocity, and the vertical impact velocity on the particle size measurement results, the feasibility of the non-invasive measurement method is proved, and it is found that the particle size error is the smallest when the vertical impact velocity is used, with the error of less than 10 % for all five particle sizes.