title: Magnetic Resonance Imaging measurements of a water spray upstream and downstream of a spray nozzle exit orifice.
abstract: Sprays are dynamic collections of droplets dispersed in a gas, with many industrial and agricultural applications. Quantitative characterization is essential for understanding processes of spray formation and dynamics. There exists a wide range of measurement techniques to characterize sprays, from direct imaging to phase Doppler interferometry to X-rays, which provide detailed information on spray characteristics in the "far-nozzle" region (≫10 diameters of the nozzle). However, traditional methods are limited in their ability to characterize the "near-nozzle" region where the fluid may be inside the nozzle, optically dense, or incompletely atomized. Magnetic Resonance Imaging (MRI) presents potential as a non-invasive technique that is capable of measuring optically inaccessible fluid in a quantitative fashion. In this work, MRI measurements of the spray generated by ceramic flat-fan nozzles were performed. A wide range of flow speeds in the system (0.2 to >25m/s) necessitated short encoding times. A 3D Conical SPRITE and motion-sensitized 3D Conical SPRITE were employed. The signal from water inside the nozzle was well-characterized, both via proton density and velocity measurements. The signal outside the nozzle, in the near-nozzle region, was detectable, corresponding to the expected flat-fan spray pattern up to 3mm away. The results demonstrate the potential of MRI for measuring spray characteristics in areas inaccessible by other methods.
authors.affiliation: MRI Centre, Department of Physics, UNB, Fredericton, NB, Canada. Electronic address: mast@unb.ca.
authors.forename: Igor
authors.initials: I
authors.lastname: Mastikhin
authors.affiliation: MRI Centre, Department of Physics, UNB, Fredericton, NB, Canada.
authors.forename: Aidin
authors.initials: A
authors.lastname: Arbabi
authors.affiliation: Spraying Systems Co., Spray Analysis and Research Services, Wheaton, IL, USA.
authors.forename: Kyle M
authors.initials: KM
authors.lastname: Bade
keywords: Flows; Magnetic Resonance Imaging; Single-point imaging; Sprays; Velocity mapping