METHOD FOR OPERATING A NUCLEAR MAGNETIC RESONANCE FLOW METER AND NUCLEAR MAGNETIC RESONANCE FLOW METER

摘要

The invention relates to a method for measuring the flow rate of a multi-phase medium flowing through a measuring tube, by means of a nuclear magnetic resonance flow meter comprising a pre-magnetization device and a measuring device, said pre-magnetization device implementing at least two pre-magnetization paths of different lengths L1, L2,.... The aim of the invention is to provide a method which can be used to measure the flow rate of a multi-phase medium in a simplified manner. For this purpose, a measuring device is used which implements, at the end of each pre-magnetization path, 2D tomography in the measurement tube cross-sectional plane with stratification in the z direction; the measurement tube cross-sectional plane is subdivided into layers that are thin compared to the measurement tube diameter; nuclear magnetic resonance measurements are carried out in every layer to determine measurement signals, using pre-magnetization paths of different lengths; the flow rates are measured in every layer based on the measurement signals; and the time T1 is determined from the signal ratios of the amplitudes of the measurement signals in every layer.