Validation of magnetic resonance thermometry through experimental and computational approaches

Recent innovations in Magnetic Resonance Thermometry (MRT) techniques provide a noninvasive means to gather three-dimensional, full field temperature measurements at millimeter resolution. Using the linear relationship between temperature and the proton resonant frequency (PRF), MRT can accurately and non-invasively measure temperature in turbulent flows through complex geometries with exceptional access, even for flows that would be obscured to conventional diagnostic techniques. Accurate flow temperature measurements in complex passages is critical for applications in several fields, including in vivo body temperature measurements during thermal therapies and film cooling passages in gas turbine blades. When combined with Magnetic Resonance Velocimetry (MRV), MRT provides an accurate, non-invasive and robust flow diagnostic method capable of enabling increased understanding of thermal-fluid phenomena. The flow configuration under investigation in this study is a jet in a cross-flow and consists of two separate cases. The standard case consists of a single heated inlet jet at 44 °C (Reynolds number 4,700), inclined at 30 degrees and 6 mm in diameter mixing turbulently with a uniform bulk flow at 14 °C (Reynolds number 26,800). For the inverted case, the temperatures of the jet and bulk flow are reversed. The results of this study are compared to previous experimental work to further validate MRT as a temperature measurement technique and provide detailed data sets for comparisons with numerical simulations. In addition, Large Eddy Simulations (LES) are conducted over this same flow configuration and serve as an additional means to compare with the MRT measurements.