Optimization of electrode and contraction section of 90° bent electromagnetic flowmeter using CFD simulation

Abstract

Currently, electromagnetic flowmeters must typically be inserted into a straight pipe, which usually requires a larger installation space. To improve installation adaptability, a novel right-angled electromagnetic flowmeter is proposed. As the measurement signal of the electromagnetic flowmeter is closely related to the flow state of its internal fluid, a large-eddy simulation (LES) was used to study the influence of the shape of the electrode and the contraction section of the flowmeter on the flow characteristics inside the flowmeter to reveal the relationship between them along with the measurement accuracy. A comparison between the numerical results and the experimental results was also performed. The velocity fluctuations of the monitoring points around the cone and flat electrodes were compared, and it was found that the overall measurement error of the cone electrodes was smaller than that of the flat electrodes. The experimental results showed that the pulsation of the voltage signal measured from the cone electrode is smaller than that of the flat electrode. In addition, the absolute value of the error in the small flowrate is much smaller than that of the flat electrode. Consequently, the measurement performance of the cone electrode is better. In addition, the largest velocity fluctuation occurred between the electrode wall and tube wall, indicating that installing the coil should avoid exciting strong magnetic fields here.