宽频超声衰减法测量河流泥沙粒径分布

为了研究宽频超声波通过河流泥沙悬浊液的声衰减谱中包含泥沙的颗粒粒度信息,采用超声耦合相模型和散射模型的叠加描述河流泥沙悬浊液中超声衰减行为,宽频超声换能器测量得到2～7.5MHz间泥沙悬浊液声衰减谱,结合独立模式的最优正则化反演算法,获得了相同体积浓度、不同粒径分布下和相同粒径分布、不同体积浓度下泥沙的颗粒粒径分布。结果表明,宽频超声衰减法能较好地区分3种不同粒径分布的泥沙,并且在体积浓为3.8%～8.5%范围间,测量得到的平均粒径受浓度变化影响较小。将超声法测量结果与显微镜图像法测量结果相比较,两种方法得到的粒径分布趋势较为一致,平均粒径较为吻合。

Particle Size Distribution Measurement of Sediment with Broad Band Ultrasonic Spectrum Method

In order to research the information about particle size distribu-tion provided by the attenuation spectrum of broad band ultrasonic waves through the suspension,combined with the optimum regularization tech-nique inverse algorithm,the particle size distributions of sediments under different volume fractions and different particle size distribution were ob-tained according to the attenuation prediction of coupled phase model plus a scattering model and experimental attenuation spectrum at frequencies ranges from 2～7.5 MHz.The results showed that the broad band ultrasonic spectrum method was able to distinguish the sediments with the different particle size distributions.The change of concentration was of little influ-ence to the measured mean diameter.The measurement results of ultrason-ic attenuation spectrum method agreed well with the microscope image measurement results.