Profile Measurement Of Pneumatically Conveyed Particles Based On Multi-sensor Information Fusion

The transportation of solid particles by pneumatic pipes is widely used in many industrial production processes.Online continuous measurement of the crosssectional distribution of pneumatically conveyed particles in large industrial pipelines is beneficial for optimizing production parameters and improving the utilization efficiency of raw materials.However,the high complexity of gas-solid two-phase flows and the limitations of existing methods in practical applications make the real-time measurement of the cross-sectional distribution of particles in large industrial pipes extremely challenging.In this study,a measurement system that integrates electrostatic and acoustic emission sensors is proposed to tackle the problem.The main research and innovative points of this dissertation are as follows:(1)A pneumatic particle measurement method combining electrostatic and acoustic emission sensors measurement data is proposed.The velocity and relative volumetric concentration of particles are measured by the electrostatic sensor combined with the cross-correlation algorithm and the root mean square charge level of the electrostatic signals.The energy characteristics of the acoustic emission signals generated by the collision of particles and a waveguide component are calculated to derive the particle size and mass flow rate with the assistance of particle velocity.(2)A measuring system combining electrostatic and acoustic emission sensors is designed.According to the flow characteristics of gas-solid two-phase flows and the measurement characteristics of both types of sensors,the non-invasive electrode,invasive electrode and acoustic emission sensor are integrated into a sensor head.This sensor head comprises 32 pairs of electrodes and 4 groups of acoustic emission sensors,and each pair of electrodes are arranged upstream and downstream of the flow direction.The measurement signals are amplified and filtered by a dedicated signal conditioning unit and then converted to digital form before being sent to the host computer for processing.(3)A large-scale square-shaped pipe section was built,and experimental tests were conducted under 30 different transport velocity and mass flow rate conditions.The velocity and relative volumetric concentration profiles of particles are obtained by applying cubic Spline interpolation method to the measurement results from intrusive electrode sensors,and compared with the corresponding results from the non-intrusive electrode sensors.The mass flow rate distribution of particles are represented by applying 3D histograms to the measurement results from acoustic emission sensors.Experimental results show that the proposed technique is capable of measuring the distribution of pneumatically conveyed particles on the whole pipe cross-section.