Experimental Study On Ultrasonic Measurement Of Particle Size In High-concentration Solid-liquid Two-phase Flow

It is a new research direction to use ultrasonic technology to measure the particle phase scale spectrum in a mixed solution.The core of this technique is whether the relation between the sound attenuation coefficient and the particle size of suspension is reasonable.However,up to now,the relation expression is still not clear in the case of a thick phase.To solve the problem,it is necessary to correlate the characteristics of the dispersed and continuous phases in the suspension with the complex wave number of the acoustic wave.This paper mainly aims at the technical problem of particle size spectrum measurement in suspension by ultrasonic technology,and carries out the following three aspects of work.(1)The ultrasonic suspension particle scale measuring system had been designed and built.In order to solve the limitation of measuring parameter selection and measuring sensitivity,a set of constant temperature ultrasonic pulse echo detection device was designed.On the basis of setting up the measuring system and detecting device,the selection,collection and conversion of the particle size signals in the suspension studied in this paper were realized.(2)The characteristics of particle suspension,including particle size,solid phase concentration,solution volume,and the correlation between sound wave frequency and sound path,had been measured experimentally,on the test platform.And the relationship between the characteristics of particle suspension and the change of sound attenuation was determined.(3)The synergy study of experimental and numerical simulation results had been carried out.For the two models defined in this paper,namely the coupling phase model and the core-shell model,the predicted value of acoustic attenuation was consistent with the experimental value when the volume fraction of suspension is lower than 0.40.It was confirmed that when the range of volume fraction was from 0.10 to 0.40,both mathematical models were suitable for analyzing the size of suspended particles by the acoustic attenuation coefficient method.On this basis,a correction coefficient suitable for the prediction value of the sound attenuation coefficient of silica suspension is proposed to further improve the prediction accuracy of the model.In this paper,the mathematical model and experimental measuring device were determined to provide technical support for further ultrasonic particle size measurement of solid particle suspension.