基于超声回波重组相位分析的颗粒粒径测量方法

将超声波作用于沉降的颗粒时，由于颗粒的移动，超声回波会出现相位差异。该文通过对测量杯中某一确定深度处的回波信号进行相位分析和重组，发现重组后信号的频率可以计算出粒径；并分别对两种不同粒径分布的聚甲基丙烯酸甲酯(PMMA)微球悬浮液进行了超声波信号采样重组和去噪的实验，实验结果经小波时频方法分析后，证实了颗粒粒径分布与重组信号频率构成的确存在很高的相关性。

Particle size measurement based on ultrasonic echo phase analysis and recombination

Constantly emitting ultrasonic waves will generate stable echoes in groups when they encounter an object. And when they are used to detect the settling particles, the phase differences of ultrasonic echoes will appear owing to particle movement. By recombining and analyzing the amplitude signal of the ultrasonic echoes at any fixed depth, the frequency distribution associated with the particle size distribution can be obtained. In this paper, ultrasonic echo signals were sampled and recombined from two suspensions of polymethyl methacrylate (PMMA) with different particle size distributions, using the UT350 ultrasonic pulse transceiver. After then, using the method of wavelet time-frequency analysis, a strong link was discovered between the particle size distribution and the frequency distribution of the combined signal. In addition, characterizing the content of the particles based on the intensity percentage of the frequency, we obtained the particle size distribution of the samples. The results show that this method has good discrimination for samples, can reflect the particle size distribution of the particles, indicating that it has good prospects for application.