The Development Of Focusing Ultrasound Measurement System For Sediment Concentration And Particle Size Distribution

The particle size distribution of suspended sediment is one of the main parameters in the detection of natural water bodies.Many fields such as water pollution research,water resources utilization and management,land use planning of water area,construction and maintenance of water conservancy projects and so on made a high demand on the accurate metering of the particle size distribution of suspended sediment.Based on the ultrasonic attenuation effect,a method measuring the particle size distribution of suspended sediment based on the focused ultrasonic transducer is proposed in this paper.Combined with the artificial bee colony inversion algorithm,the particle size distributions of suspended sediment with three different distributions were studied.The main works completed in this paper are:(1)A method measuring the particle size distribution of suspended particles under the focused sound field is proposed.A self-focusing ultrasonic transducer was designed and fabricated,and the ultrasonic attenuation experiment system was established.According to the experimental conditions,the screening method was used as the contrast method.Accordingly,the experimental method of the screening method was designed.(2)Based on the ultrasonic attenuation effect,the ultrasonic attenuation experiments were carried out on the experimental device.Three sets of samples A,B,and C with different particle size distributions were obtained by sieving method,and ultrasonic experiments were conducted at different ultrasonic frequencies.The ultrasonic feedback waveforms were processed by the wavelet transform.Combined with Fourier transform,the attenuation coefficients of the three samples under different frequencies were obtained.(3)The ECAH model was adopted as the theoretical model,combined with the attenuation coefficients obtained by the ultrasonic attenuation experiments,the particle size distribution values of the three samples were inversed according to the artificial bee colony algorithm.Within the experimental range of this paper,the maximum relative errors of samples A,B and C are within ±35% and the average relative errors are less than ±1%,and the mean square error of the errors are in the range of ±6 %,showing that the proposed method has a relatively good measurement effect on the suspended particle size distribution in the specific frequency and particle size range.