Visualization of Turbulent Kinetic Energy Using Magnetic Resonance Velocimetry on Cross Jet Flow

This presentation is part of the 2023 Magnetic Resonance Velocimetry (MRV) Challenge and highlights the collaborative research conducted by a team of researchers from Hanyang University. The study focused on MRV experiments conducted in a square water channel containing cubic elements positioned at the center and sides, with an injection point located behind the first cubic structure. The main flow exhibited a constant flowrate of 22.2 liters per minute (LPM) at a temperature of 20.5 degrees Celsius, while the injection flow had a steady flowrate of 1 LPM at a temperature of 33.5 degrees Celsius. To examine the resulting temperature field from the mixing of the two flows, a gradient echo sequence was employed for three-dimensional temperature mapping. The echo time (TE), a crucial parameter in proton resonance frequency thermometry, was varied during the experiments. Four reference oil phantoms were strategically placed at the edges of the test section to correct phase errors caused by system inhomogeneity. The analysis involved a comparison between phase-corrected and non-phase-corrected approaches, evaluating the temperature field and measurement uncertainty under different TE conditions. Additionally, the three-dimensional turbulent kinetic energy (TKE) field was quantified to demonstrate the MRV's capability for measuring TKE in complex flows. The results indicated that temperature data obtained with longer TE values exhibited higher measurement errors due to turbulence-induced signal loss. The experimental apparatus has been shared with MRV professional research teams worldwide for benchmark analysis, aiming to enhance the utility and applicability of MR-based measurements.