P1611 - Method and system for calibration-free determination of a flow velocity of an electrically conductive fluid

The present invention refers to a method and a system for calibration-free determination of a flow velocity of an electrically conductive fluid (7). Each of two field coils (1a, 1b), which are designed to be positioned at a distance from each other in the respective fluid (7) and electrically insulated from the respective fluid (7), is provided simultaneously with a pulsed electrical current, wherein the two pulsed electrical currents are oppositely directed, so that a primary magnetic field is created leading to oppositely directed eddy currents induced by the primary magnetic field in the surrounding fluid (7), thereby creating a secondary magnetic field in the respective fluid (7). The secondary magnetic field is measured after the pulsed electrical currents by two magnetic field sensors (3a, 3b), which are designed to be positioned at a distance from each other in the respective fluid (7) and electrically insulated from the respective fluid (7), wherein the flow velocity is calculated from a measured time-dependent strength of the secondary magnetic field and/or its time derivative.