Radio frequency pulse marking of nuclear magnetization for magnetic flow metering: The impact of the flow profile

Abstract

This study explores how magnetization manipulation occurs in a flowing medium over a pipe geometry using nuclear magnetic resonance methods. In particular, the experimental conditions on radio frequency pulsing and the signal detection are studied in an ultra-low frequency regime of a few kilohertz. An analytical model of the magnetization preparation is presented, which calculates the magnetization distribution of an excited flowing segment. The effective flip angle distribution is mapped to simulate the temporal development of the magnetization in the segment. The simulation results are compared to the experimental data from a flow metering setup. As a result, the quantitative impact of the flow profile on the magnetic signal is shown.