Electrostatic Charge Distribution-Based Direct Velocity Tomography Method for Gas–Solid Two-Phase Flow

Abstract

Electrostatic direct velocity tomography method (EDVT) based on electrostatic tomography (EST) is a technology that uses the induced charge signal on the electrode surface through an image reconstruction algorithm to obtain the particle velocity distribution of gas-solid two-phase flow. To simplify the calculation, EDVT assumes that the charge in the imaging region is uniformly distributed. However, due to the complexity of gas–solid flow, this assumption cannot be satisfied, which often brings great measurement errors. To solve the problem, this article proposes an electrostatic charge distribution-based direct velocity tomography (ECDDVT) method by introducing charge distribution information to improve the cross-correlation sensitivity matrix. To evaluate the effect of the particle velocity distribution reconstruction method, this article established an evaluation platform based on a three-dimensional (3-D) simulation of gas–solid flow field and electrostatic field. By assigning the weight value of the number of particles in different pixel units, a more accurate method for measuring the average particle velocity can be obtained. The simulation results and the experiment results of the belt type electrostatic velocity measurement facility show that the performance of the proposed ECDDVT in terms of image correlation coefficient and absolute percentage error (APE) is better than EDVT. The experimental results of the gas–solid two-phase flow rig show that the ECDDVT method can better reflect the particle velocity in the center of the pipe.