Magnetic resonance velocimetry (MRV) is an experimental method to obtain
velocity fields in
fluid mechanics. MRV is based on the phenomenon of
nuclear magnetic resonance and adapts a medical
magnetic resonance imaging system for the analysis of technical flows. The velocities are usually obtained by
phase contrast magnetic resonance imaging techniques. This means velocities are calculated from phase differences in the image data that has been produced using special gradient techniques. MRV can be applied using common medical MRI scanners.[2] The term magnetic resonance velocimetry became current due to the increasing use of MR technology for the measurement of technical flows in
engineering.[3]
Applications
In engineering MRV can be applied to the following areas:
Analysis of technical flows in complex geometries (
separation, recirculation zones)
In contrast to other non-invasive
velocimetry methods such as
PIV or
LDA, no optical access is required. Besides, no particles have to be added to the fluid. Thus, MRV enables to analyze the complete flow field in complex geometries and components.[4]
Based on the fact that common MR scanners are designed to detect the
nuclear magnetic resonance of hydrogen protons, the tested applications are limited to water flows. Common fluid mechanical scaling concepts compensate this limitation. To achieve the spatial resolution, single data acquisition steps have to be repeated a great number of times with slight variations. Thus, MRV technology is limited to
steady or periodical flows.[5]