Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 57 for “"Mixing efficiency"”.
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A generalized approach to increased mixing efficiency for viscous liquids.
Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering.
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Computational and experimental determination of the mixing efficiency of a microfluidic serpentine micromixer
In microfluidics, efficiency and mixing time are the greatest disadvantages. These parameters hinder the application of microfluidic devices for biochemical and immunological assays. However, once these disadvantages have been overcome by optimizing the parameters of the microfluidic device, it …
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The efficiency of turbulent mixing in stratified fluids
Mixing is a common feature of stratified fluids. In stratified fluids the density varies with the height. This is true for the most fluids in geophysical environments, like lakes, the atmosphere or the ocean. Turbulent mixing plays a crucial role for the overall energy budget of the earth and has …
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Some of the factors affecting the operation of a screw conveyor type mixer
… The purpose of this was to prevent all of the mixing action from occurring in the first unit and to show an incomplete picture of the mixer operation. These preliminary investigations also showed the maximum particle size usable in the mixer without obtaining excessive size reduction during …
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Design of Flow Reactors for the Continuous Synthesis of Nanoparticles
… 7.3 2.2 nm and 2.1 0.5 nm by controlling mixing efficiency and speciation of gold precursor. In order to understand the effect of mixing on the size of Au NPs, a novel CFD method is established based on a published algorithm to simulate the accurate concentration distribution, avoiding …
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Passive micromixers for DNA analysis using CFD modelling
Mixing efficiency is an important issue in the design of micromixers, since effective mixing is required between Deoxyribonucleic acid (DNA) sample and restriction enzyme for a fast digestion process. Mixing is improved by chaotic advection through serpentine mixing channels. This leads to the …
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On vortex rings impacting a sharply-stratified interface
… understand the flow instability and subsequent mixing induced by the impinging vortex ring. Our findings demonstrate that there exists a critical Richardson number, corresponding to a mixing transition, beyond which the mixing efficiency is constant. Using a novel Stereo Particle Image …
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Understanding the evolution of miscible viscous fingering patterns
… process, such as volumetric sweep and mixing efficiency, depend strongly on the type of pattern created by the uneven front of the less viscous fluid. The interface created from these fingering patterns affects mixing, and therefore understanding how these patterns evolve is of critical …
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Numerical representations of fluid mixing
… together with an analysis of their associated mixing processes which find applications to Industrial mixing and also to the environment. The mixing efficiency has been viewed from two perspectives namely the tracking of a selection of fluid particles, and also the simulation of the dispersive …
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Experimental Investigation of a Flush-Walled, Diamond-Shaped Fuel Injector for High Mach Number Scramjets
… diamond injectors exhibited 10% and 15% lower mixing efficiency than the round injector, respectively. The total pressure loss parameter of the aligned diamond was 22% lower than the round injector, while the addition of yaw angle improved the total pressure loss parameter to 34% lower than the …
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Mixing in stably stratified turbulent flows: improved parameterizations of diapycnal mixing in oceanic flows
Mixing of fluid with different properties across a gravitationally stable density interface, due to background turbulence is an ubiquitous phenomenon in both natural and engineered flows. Fundamental understanding and quantitative prediction of turbulent mixing in stratified flows is a challenging …
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Internal hydraulic jumps with upstream shear
… front turbulent jump. At low shear, the 2D mixing efficiency is constant across simulations. As shear increases, the basic two-layer theories no longer provide solutions. Numerical simulations show that entrainment becomes significant as the shear increases, and adding entrainment and shape …
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Internal hydraulic jumps with upstream shear
… front turbulent jump. At low shear, the 2D mixing efficiency is constant across simulations. As shear increases, the basic two-layer theories no longer provide solutions. Numerical simulations show that entrainment becomes significant as the shear increases, and adding entrainment and shape …
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Heat transfer in mixing vessels at low Reynolds numbers. An experimental study of temperature profiles heat transfer rates and power requirements for mechanically agitated vessels operating at low Reynolds numbers.
… study investigates experimentally the laminar mixing and heat transfer of a range of helical ribbon and anchor impellers for both Newtonian and inelastic non-Newtonian fluids. The work also correlates the experimental data empirically in the form of dimensionless groups. In order to estimate …
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Computational fluid dynamic (CFD) optimization of microfluidic mixing in a MEMS steam generator
The challenge of achieving rapid mixing in microchannels is addressed through a computational fluid dynamics (CFD) study using the ADINA-F finite element program. The study is motivated by the need to design an adequate mixing chamber for aqueous chemical reactants in a micro steam generator. The …
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The geometry of mixing in stratified flows: theory, experiments, observations and simulations
… with different densities irreversibly mix. Mixing is a process that happens on (very) small scales but is known to have a leading order impact on large-scale ocean circulation, for example. Quantifying the rate at which turbulence mixes density differences is therefore crucial. However, it …
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Energetics and mixing in stratified turbulent flows
Turbulent mixing has an important influence on many physical processes in the ocean. For example, the upwelling of water through the stably stratified ocean interior, needed to close the global circulation, is only possible through the enhanced vertical mixing resulting from turbulence. The …
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Jet Fluid Mixing Control Through Manipulation Jet Fluid Mixing Control Through Manipulation of Inviscid Flow Structures
Rapid mixing is crucial for the efficient and environment-friendly operation of many industrial and propulsion devices involving jet flows. In this dissertation, two methodologies, self-excited nozzles and radially lobed nozzles, are studied and presented in order to enhance mixing in the near …
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Development of a to-scale fluid mixing visualization process for analysis of cold-flow mixing
… is central to the overall torrefaction system efficiency. In order to analyze the mixing efficiency in a swirl-type mixer such as the design proposed for the small-scale torrefaction system, a project was designed to visualize mixing in an annular mixer. A to-scale cold-mixing system was …
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Polymeric nanocapsules for pharmaceutical applications
… with controlled size thank to the high mixing efficiency inside the mixing chamber. Drug release tests have been performed and show that the release from nanocapsules is slower than from nanspheres. Moreover, drug release in the first hours of release depends on a diffusive mechanism …
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