Measurement of solids velocity and concentration at an elbow using wire-mesh electrostatic sensors

In order to monitor the pneumatic conveying pipeline in real time and improve the combustion efficiency in boiler furnace, the particle velocity and concentration distributions in pneumatic conveying pipeline need to be measured. In this study, electrostatic sensors with wire-mesh structure are applied to measure the particle velocity and concentration distributions at the elbow of the pneumatic conveying pipeline. To study the characteristics of the sensors, firstly, the finite element model of the wire-mesh electrostatic sensors is built. According to the finite element simulation result, the design of the wire-mesh electrostatic sensors is optimized, which makes the wire-mesh electrostatic sensors have a higher and more uniform sensitivity distribution. Experiment study was conducted in a laboratory-scale particle flow test rig. The cross correlation calculation of the electrostatic signals from the wire-mesh electrodes placed at corresponding upstream and downstream planes is conducted to estimate the axial velocity profile of the particles. In addition, the root mean square values of the electrostatic signals from the wire-mesh electrodes placed at the same plane are reconstructed, and the relative concentration distribution of the particles is obtained. It is concluded from the experiment results that the proposed wire-mesh electrostatic sensors can be used to measure the particle velocity and concentration distributions at the 90° elbow of the pneumatic conveying pipeline.