3D motion-sensitised SPRITE MRI of hydrodynamic cavitation
University of New Brunswick
A liquid flowing in a pipe will experience pressure variations due to changes in the pipe geometry (for example, the narrowing of the pipe diameter at a constriction). For a sufficiently fast flow speed, the local pressure can drop below the vapour pressure of the liquid, which results in the formation of bubbles (hydrodynamic cavitation). The measurement of this phenomenon requires a non-optical and non-invasive technique; therefore, it is well-suited for study with magnetic resonance imaging (MRI). MRI is an inherently three-dimensional technique that can be used to measure several parameters of the flow, including density, void fraction, and flow velocity. Three-dimensional void fraction and velocity images were acquired of a cavitating flow through a pipe constriction by using a motion-sensitised version of the Conical SPRITE MRI pulse sequence. As a pure phase encoding technique, SPRITE is well-suited to study fast, turbulent, two-phase flow systems (i.e. characteristics of cavitating flow). As far as we know, this combination of information is not available using any other measurement technique.