Data from: Reconstruction of velocity fields in electromagnetic flow tomography

Electromagnetic flow meters (EMFMs) are the gold standard in measuring flow velocity in process industry. The flow meters can measure the mean flow velocity of conductive liquids and slurries. A drawback of this approach is that the velocity field cannot be determined. Asymmetric axial flows, often encountered in multiphase flows, pipe elbows and T-junctions, are problematic and can lead to serious systematic errors. Recently, electromagnetic flow tomography (EMFT) has been proposed for measuring velocity fields using several coils and a set of electrodes attached to the surface of the pipe. In this work, a velocity field reconstruction method for EMFT is proposed. The method uses a previously developed finite-element-based computational forward model for computing boundary voltages and a Bayesian framework for inverse problems. In the approach, the vz-component of the velocity field along the longitudinal axis of the pipe is estimated on the pipe cross section. Different asymmetric velocity fields encountered near pipe elbows, solids-in-water flows in inclined pipes and in stratified or multiphase flows are tested. The results suggest that the proposed reconstruction method could be used to estimate velocity fields in complicated pipe flows in which the conventional EMFMs have limited accuracy.

电磁流量计（Electromagnetic Flow Meters, EMFMs）是过程工业中测量流体流速的金标准。此类流量计可测量导电液体与浆料的平均流速。该方法的一处缺陷在于无法获取完整的流速场分布。在多相流、管道弯头及T型三通场景中常见的非对称轴向流会引发测量问题，并可能导致严重的系统误差。近年来，研究者提出了电磁流动层析成像（Electromagnetic Flow Tomography, EMFT）技术，通过安装于管道外壁的多组线圈与电极阵列来实现流速场的测量。本研究提出了一种适用于EMFT的流速场重构方法。该方法依托已有的基于有限元的计算正演模型来计算边界电压，并采用针对反问题的贝叶斯框架。该方法在管道横截面上估算沿管道纵轴分布的流速场vz分量。研究对多种非对称流速场进行了测试，包括管道弯头附近的流场、倾斜管道内的固水两相流，以及分层流或多相流场景下的流场。实验结果表明，所提重构方法可用于估算传统电磁流量计精度受限的复杂管道内流速场。