Theoretical analysis of the two-coil method for measuring fluid flow using nuclear magnetic resonance

A theoretical study of the application of pulsed nuclear magnetic resonance (NMR) to the measurement of fluid flow has been made. Calculations of detector signal line shapes, for a two-coil NMR laboratory experiment, were performed using a computer to determine the appropriate choice of flow signature. Results of calculations are presented showing the sensitivity of the method to various experimental parameters. The position of the received peak signal, in time, was found to correlate directly with mean flow velocity. However, the shape of the received signal was observed to depend markedly upon the state of flow, i.e., laminar, turbulent (plug). Hence, accurate determinations of flow required a knowledge of flow type. The theoretical calculations provided a better understanding of the potential of NMR for measuring fluid or blood flow.