Doctor of Philosophy (PhD)
Mechanical and Industrial Engineering
A confocal micro-particle image velocimetry (C-μPIV) technique along with associated post-processing algorithms is detailed for obtaining three dimensional distributions of nano-particle velocity and concentrations at select locations of the 2.5D (pseudo 3D) Poly(methyl methacrylate) (PMMA) and ceramic micro-model. The designed and fabricated 2.5D micro-model incorporates microchannel networks with 3D wall structures with one at observation wall which resembles fourteen morphological and flow parameters to those of fully 3D actual reservoir rock (Boise Sandstone) at resolutions of 5 and 10 μm in depth and 5 and 25 μm on plane. In addition, an in-situ, non-destructive method for measuring the geometry of low and high resolution PMMA and ceramic micro-models, including its depth, is described and demonstrated. The flow experiments use 860 nm and 300 nm fluorescence-labeled polystyrene particles, and the data is acquired using confocal laser scanning microscopy. Regular fluorescence microscopy is used for the in-situ geometry measurement along with the use of Rhodamine dye and a depth-to-fluorescence-intensity calibration, which is linear. Monochromatic excitation at a wavelength of 544 nm (green) produced by a HeNe continuous wave laser was used to excite the fluorescence-labeled nanoparticles emitting at 612 nm (red). Confocal images were captured by a highly sensitive fluorescence detector photomultiplier tube. Results of detailed three dimensional velocity, particle concentration distributions, and particle deposition rates from experiments conducted at flow rates of 0.5 nL/min, 1 nL/min, 10 nL/min and 100 nL/min are presented and discussed. The three dimensional micro-model geometry reconstructed from fluorescence data is used as the computational domain to conduct numerical simulations of the flow in the as-tested micro-model for comparisons to experimental results using dimensionless Navier-Stokes model. The flow simulation results are also used to qualitatively compare with velocity distributions of the flowing particles at selected locations. The comparison is qualitative because the particle sizes used in these experiments may not accurately follow the flow itself given the geometry of the micro-models. These larger particles were used for proof of concept purposes, and the techniques and algorithms used permit future use of particles as small as 50 nm.
Upadhyay, Jagannath, "Mobility of Nano-Particles in Rock Based Micro-Models" (2018). LSU Doctoral Dissertations. 4546.
Nikitopoulos, Dimitris E.