Fluctuations in Flows by NMR

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9404778 Fukushima The potential use of nuclear magnetic resonance imaging (NMRI) for measuring fluctuating parameters in two-phase flow will be explored. The two-phase parameters include solids and liquid velocity fluctuations, mixture density fluctuations, diffusion coefficients and velocity cross-correlations. The key issue is the reduction of the time necessary for each imaging. Other objective is developing techniques necessary to interpret the fluctuations and their correlations determined by NMRI, and to define the limits of the method. Current optical methods are not suitable for most liquid-solid mixture systems which are opaque, particularly in industrial applications. The Lovelace Institutes will provide new equipment for the reduction of eddy currents in the magnets, which is the main hardware requirement of the project. The gradient switching speed for individual measurements in the preliminary tests has been increased by three orders of magnitude by controlling the eddy currents. It is expected that velocity imaging in a two-dimensional domain could be performed in 0.05 seconds for a 64X64 mesh, which would be qualitatively superior to previous results and would be sufficiently fast to be used for velocity fluctuations in turbulent flows with relatively low Reynolds number. The experiments will be performed in a relatively simple geometry for which there are reference data on two-phase fluctuating parameters. The budget covers educational type of expenses, in collaboration with the University of Washington in Seattle. Advanced NMRI has application as a versatile non-destructive measuring technique to control multiphase flow systems in chemical manufacturing and other processing industries. If successful, the present project will demonstrate the feasibility of using NMRI to a large group of two-phase flow measurements, with important impact on advancing the science (new instrumentation, reference sets of data for opaque multiphase system s) and technology (nonintrusive in-situ sensors) of multiphase flow. ***