Velocity-sensitive magnetic resonance imaging (MRI) is considered a promising clinical tool to determine velocity and turbulence fields in blood vessels and thus detect cardiovascular diseases before the onset of clinically relevant pathologies. Our own work has shown that MRI-based flow measurement is prone to errors. These problems are hardly known, as there are no standardized test routines for MRI devices to ensure the quality of such measurements for clinical applications. So far, the quality of MRI flow measurement is completely dependent on the MRI device, the manufacturer's MRI pulse sequence and the experience of the medical staff. At the MRI flow lab, a DFG equipment center for the further development of MRI measurement technology for fluid mechanics, test protocols and test systems are being developed for this purpose. As a reference, high-precision data is recorded using our own established MRI gold standard method. After validation of the methods, application-oriented tests are carried out as part of an interlaboratory study at clinical sites with MRI devices from different manufacturers. 

In view of the decarbonization of society, alternatives to the combustion of natural gas in aircraft gas turbines are needed. One possibility is green hydrogen as a substitute fuel. However, the combustion of high proportions of hydrogen in aircraft gas turbines poses a challenge regarding NOx emissions, flashback risk and thermoacoustic instabilities. To optimize gas turbines for the use of hydrogen as fuel, data on the flow field and in particular the mixing of different gas flows are important. While conventional measurement methods reach their limits here and CFD models depend on validation data, MRI can make this data available.

The cooling circuit is crucial for the safe operation of nuclear power plants. During operation, solid particles (debris) accumulate in filter grids at the base of the fuel element, which increasingly obstruct the filter grid. Our project partners from the  Framatome GmbH (Erlangen, Germany) have been investigating the deposition behavior using computational fluid dynamics (CFD) for several years. MRV is capable of providing a detailed, three-dimensional velocity field in the partical laden flow and the deposition of the particels in the filter. The experimental data is used to verify the CFD methods, which can be applied to ensure the safety of European nuclear power plants.

To advance the understanding of thermal-hydraulic behaviour in sub-channels of rod bundle geometries, this project investigates two-phase flow in reactor-like conditions using Magnetic Resonance Velocimetry (MRV). The objective is to generate high-resolution, three-dimensional flow data to support the validation and refinement of multiphase computational fluid dynamics (CFD) models of adiabatic and boiling two-phase flows. Experiments are conducted in a non-proprietary test section equipped with both swirl- and split-type spacer grids, with air injected at defined locations to produce well-controlled bubbly flow conditions. A broad range of flow regimes is explored, providing detailed measurements of velocity fields, bubble distributions, bubble sizes, and full boundary conditions. The University of Rostock performs 3D MRV measurements in a horizontal, large-scale loop operating at elevated Reynolds numbers. At the same time, the University of Lorraine complements the study with one-dimensional NMR measurements in a vertical setup. This joint experimental campaign is conducted within the framework of the OFFERR project, in collaboration with Framatome and EDF. It aims to enhance cross-institutional collaboration through coordinated experiments and mutual research visits.