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）是过程工业领域流速测量的金标准。此类流量计可实现导电液体与浆体的平均流速测量。该方法的显著缺陷在于无法获取流场的速度分布：在多相流、管道弯头及T型管件中常见的非对称轴向流会引发严重的系统误差。近年来，研究人员提出了电磁流量层析成像（Electromagnetic Flow Tomography，EMFT）技术，通过附着于管道表面的多组线圈与电极阵列实现速度场测量。本研究提出了一种面向电磁流量层析成像的速度场重建方法：该方法采用此前开发的基于有限元的计算正演模型以计算边界电压，并结合贝叶斯框架处理反问题。该方法可在管道横截面上估算沿管道纵向轴线的速度场z向分量。研究针对管道弯头附近、倾斜管道内的固液两相流以及分层流/多相流中常见的各类非对称速度场开展了测试验证。结果表明，所提重建方法可用于传统电磁流量计精度受限的复杂管道流动的速度场估算。