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Development and Validation of an MRI-Based Method for Particle Concentration Measurement

Daniel D. Borup
Department of Mechanical Engineering Stanford University 488 Escondido Mall Stanford, California 94305

Christopher J. Elkins
Department of Mechanical Engineering Stanford University 488 Escondido Mall Stanford, California 94305

John K. Eaton
Dept. of Mechanical Engineering Stanford University 488 Panama Mall Stanford, CA 94305 USA

Аннотация

Dilute, dispersed multiphase flows are of critical importance in engineered, environmental, and biological applications. Traditional laser-based techniques are limited to data acquisition in discrete 2D planes with optical access required. Magnetic Resonance Imaging (MRI) is finding increasing use as a diagnostic for 3D measurements in complex turbulent flows where no optical access is possible. A new diagnostic called Magnetic Resonance Particles (MRP) has been developed whereby the volume fraction of dispersed microparticles in water can be measured quantitatively. Data obtained for dilute loadings of bismuth, graphite, and titanium powder suspended in agar gel showed excellent agreement with theoretical predictions from the MRI literature. The spatial extent of signal disturbance was investigated using an individual stainless steel particle suspended in gel. Finally, a full-scale experiment was performed in which a streak of titanium particles was injected into a complex, turbulent channel flow. Calibration values were obtained using an integral flux method and the resulting particle concentration distribution was analyzed. The calibration values showed some disagreement with theory; this issue will be the focus of upcoming calibration experiments in a channel flow with homogeneous particle distribution.