关键词: 气固流化床, 声波, 主频, 粒径, 结块

Abstract: A model of signal main-frequency measurement was presented for the gas-solid fluidized bed to represent the quantitative relation of main-frequency and particle size,temperature, Young’s modulus and density. The acoustic emission（AE） measurement was completely non-intrusive and not affected by the background noises, and caused to human harm.The experiment based on AE measurement was performed by using a fast Fourier transform (FFT) analyzer in this study. It was found the signals main-frequency decreased with the increasing particle size, temperature, Young〖DK〗’s modulus and density. The experiment in the fluidized bed with i.d. of 150 mm showed that satisfactory agreement was obtained between calculated and experimental data with respect of the main-frequency (LLDPE, HDPE and bimodal polyethylene), and the average errors were all less than 8.3%. The scale-up feasibility of the technical process was discussed by adjusting the elastic partameter. When the AE signals main-frequency model was applied to the industrial fluidized bed of LLDPE, HDPE, bimodal polyethylene, the mean errors between calculated and experimental data were 3.9%，8.2% and 8.8% respectively. By the criterion of the sharp decrease of main-frequency and the sharp increase of amplitude, a novel approach could be developed to judge whether the fluidization runs stably, and it could replace the γ-ray measurement in the future.

Key words: 气固流化床, 声波, 主频, 粒径, 结块