Monitoring And Analysis Of Deep-Sea Flexible Mineral Transport Fluid Performance Based On Ultrasonic Technology

In deep-sea mining,hydraulic lifting is the most promising way to transport ore,and real-time monitoring of the concentration of ore particles in flexible pipelines is one of the technologies that need to be addressed in the design of deep-sea mining systems.The study of particle size and concentration of ore particles is essentially the study of particle size and concentration in two-phase flow,ultrasonic with its non-invasive,real-time and wide range of measurement characteristics in the two-phase flow particle size and concentration measurement of researchers in various countries pay much attention to.At present,ultrasonic technology is mainly used in industrial production,water conservancy engineering and environmental protection,mainly focusing on the particle size and concentration measurement of tiny particles,and less research has been conducted on the particle size and concentration measurement of oversized particles.Based on the measurement problem of oversized particles,this paper investigates the ultrasonic detection of particle size and concentration of mineral fluids from three aspects:theoretical analysis,simulation verification and experimental verification.Firstly,the conversion of ultrasonic waves at solid-liquid,liquid-solid and solid-solid interfacial waveforms and the main factors affecting ultrasonic attenuation are introduced according to the acoustic properties.Theoretically,the ECAH model,UA model,HT model and BLBL model are analyzed,and the four models are numerically simulated according to the theoretical model and the physical parameters of the actual material.The main factors affecting ultrasonic attenuation in each model are summarized according to the characteristics of each model under the conditions of different frequencies and particle sizes.In the two-phase flow of large particles,the main factor affecting ultrasonic wave attenuation is scattering attenuation,and the BLBL model is finally chosen as the theoretical basis by combining the numerical simulation results.Secondly,according to the numerical simulation results of the theoretical model,the finite element analysis software was used to simulate and verify the emission frequency,detection method of the whole experiment.The emission frequencies of 250 KHz,500KHz and 1MHz were determined;the ultrasonic penetration method(one transmitting and one receiving transducer)was used to measure the particles.Finally,the soft and hard platforms for ultrasonic wave transmission,reception and data acquisition are designed.By analyzing the propagation law of ultrasonic waves,a way of intercepting useful signals is proposed.According to the intercepted signal,the relationship between the ultrasonic wave attenuation coefficient and the signal amplitude eigenvalue showing negative correlation was analyzed in the frequency domain.The results show that the measured particle size is controlled within 10%,and the concentration error gradually decreases with the increase of concentration and can be controlled within 15%.