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Full-Text Articles in Engineering
Studies Of Multiphase Distribution And Flow In Bubble/ Slurry Bubble Columns With /Without Internals And Advanced Sustainable Construction Materials Using Sophisticated Measurement Techniques, Omar Farid
Doctoral Dissertations
"Bubble/slurry bubble columns have been widely studied and employed as multiphase flow reactors with and without vertical heat-exchanging tubes. In order to understand more deeply the effect of the dense internals on the hydrodynamics of bubble/slurry bubble column, systematic experiments were performed to visualize and quantify using the radioactive particle tracking (RPT) technique. A new methodology for implementing the radioactive particle tracking (RPT) technique has been developed to investigate the effect of the dense internals on the hydrodynamics of the bubble/slurry column reactor. Monte Carlo N-Particle (MCNP) simulation has been implemented to simulate the system to generate a large number …
Integrating Experimental Parameter Space For Granular Flow Within Polygon Tumblers, Michaela Mcmahon
Integrating Experimental Parameter Space For Granular Flow Within Polygon Tumblers, Michaela Mcmahon
Graduate Research Theses & Dissertations
Granular flows are complex phenomena bridging both fluid and solid mechanics and observed frequently in the natural world. The transitional dynamics of acceleration from solid body motion to rapid flow can affect many aspects including volume flow rates and mixing behaviors. In order to study the combination of both variables together within polygon-shaped tumblers, control systems are necessary with a corresponding user interface. This thesis reports an interface for changing variable inputs to the system. Predictions of rotation rates with corresponding interfaces with hardware connections are described. Results of image analysis verify output performance that incorporates the following variable changes: …
Computational Sodium Heat Pipe Simulation In Three Dimensions For Transient Nuclear Reactor Analysis With Variable Surface Heat Flux, Valerie Jean Lawdensky
Computational Sodium Heat Pipe Simulation In Three Dimensions For Transient Nuclear Reactor Analysis With Variable Surface Heat Flux, Valerie Jean Lawdensky
UNLV Theses, Dissertations, Professional Papers, and Capstones
Heat pipes are used to transfer heat through phase change in a liquid/vapor contained in a metal tube. They are passive devices that require no pumps to circulate the fluid and can transfer heat far more efficiently than a solid copper rod of the same diameter. They are commonly used in laptop computers where copper heat pipes filled with water take heat away from the CPU and transfer the heat to air through a heat exchanger. Heat pipes were also used in the Kilopower nuclear reactor where higher temperatures required sodium as the working fluid with stainless steel tubes. Computer …
The Return To Anisotropy Across A Jet In Crossflow, Gregory P. Sakradse
The Return To Anisotropy Across A Jet In Crossflow, Gregory P. Sakradse
Dissertations and Theses
With data from experiments on a jet of air emitting from an orifice flush with the floor of a wind tunnel providing a transverse flow, analysis is conducted to extract information about the state of anisotropy in the Reynolds stress tensor. Inflow velocities are modulated across two distinct turbulence intensity regimes while holding jet exit conditions constant, providing an opportunity to isolate effects of both jet to crossflow velocity ratio, r and the effects of the turbulence carried by the crossflow. Anisotropy in the Reynolds stress tensor is examined through anisotropy invariant maps and evolution of the function F, …
An Analysis Of Capillary Flow In Finite Length Interior Corners, Samuel Shaw Mohler
An Analysis Of Capillary Flow In Finite Length Interior Corners, Samuel Shaw Mohler
Dissertations and Theses
We analyze the mathematical robustness of slow massively parallel interior corner flows in low gravity environments. An interior corner provides a preferential orientation in low gravity environments. This is a luxury usually only found on earth. It also provides a passive pumping mechanism due to geometry of a conduit. The driving force for this flow is a pressure difference due to local surface curvature gradients. An alternative reasoning is that due to the geometrical constraints the interior corner surface energy is unbounded below. This results in the liquid wicking into corners indefinitely. Interior corner flow's main quantity of interest is …
Fixed Bottom Wind Turbine Wave-Wake Interaction, Ondrej Fercak
Fixed Bottom Wind Turbine Wave-Wake Interaction, Ondrej Fercak
Dissertations and Theses
The interest and benefits of offshore wind energy has also brought along legitimate design challenges for engineers. Most notably, the complex interaction between wind and turbine is further complicated by the addition of dynamic ocean waves. This dynamic coupling between wind, wave, and turbine is not fully understood. Even small improvements in wind turbine performance are welcome, so characterizing a fundamental dynamic in offshore energy is necessary to optimize design. Experimentation and simulation have been used to characterize inflow and turbine wakes and separately, wind-wave interactions. But only simulations have just begun to look at the wind, wave, and turbine …
Bicycle Wheel Aerodynamics Predictions Using Cfd: Efficiency Using Blade Element Method, Drew Vigne
Bicycle Wheel Aerodynamics Predictions Using Cfd: Efficiency Using Blade Element Method, Drew Vigne
Honors Undergraduate Theses
The cycling industry has long relied on expensive wind tunnel testing when designing aerodynamic products, particularly in the context of wheels which account for 10 to 15 percent of a cyclist's total aerodynamic drag. With the recent advent of Computational Fluid Dynamics (CFD), the industry now has an economical tool to supplement the wheel design process; however, the complex nature of rotating spoked wheels requires high resolution meshes to model at acceptable fidelity. This research investigates an alternative CFD method that lowers the computational cost of modeling aerodynamic bicycle wheels by modeling spokes using Blade Element Method (BEM). Two CFD …
Dynamic Effects Of Inertial Particles On The Wake Recovery Of A Model Wind Turbine, Sarah E. Smith
Dynamic Effects Of Inertial Particles On The Wake Recovery Of A Model Wind Turbine, Sarah E. Smith
Dissertations and Theses
Impacting particles such as rain, dust, and other debris can have devastating structural effects on wind turbines, but little is known about the interaction of such debris within turbine wakes. This study aims to characterize behavior of inertial particles within the turbulent wake of a wind turbine and relative effects on wake recovery. Here a model wind turbine is subjected to varied two-phase inflow conditions, with wind as the carrier fluid (Reλ = 49 - 88) and polydisperse water droplets (26 to 45µm in diameter) at varied concentrations (Φv=0.24 x 10-5 - 1.3 …
Characterization Of Inertial Particles In The Turbulent Wake Of A Porous Disk, Kristin Nichole Travis
Characterization Of Inertial Particles In The Turbulent Wake Of A Porous Disk, Kristin Nichole Travis
Dissertations and Theses
This study presents the findings of a wind tunnel experiment investigating the behaviour of micrometric inertial particles in the turbulent wake of a stationary porous disk. Various concentrations [Φv ∈ (2.95 x 10-6 - 1.22 x 10-5)] of polydisperse water droplets (diameter 13-41 µm) are compared to sub-inertial tracer particles. Hot-wire anemometry, phase Doppler interferometry and particle image velocimetry were implemented in the near and far wake regions to study the complex dynamics of the particles. Turbulence statistics and particle size distributions are presented and used to explore the particle wake interaction.
Separation Bubbles And Vortex Formation In Cavity Flows, Kartheek Ravulapati
Separation Bubbles And Vortex Formation In Cavity Flows, Kartheek Ravulapati
Doctoral Dissertations and Master's Theses
This research is a computational fluid dynamic study of the formation of vortices and separation bubbles in a square cavity as well as in a cylindrical cavity. Whereas there has been previous research work on the problem of a free stream over different types of cavities, like open and closed cavities or lid driven cavities, this research on an inlet induced flow inside a square cavity lead to unusual and interesting basic fluid dynamical phenomena. The flow in a square cavity and in a cylindrical cavity is simulated over a range of Reynolds numbers and the appearance of separation bubbles …
Fluid-Structure Interaction And Multidisciplinary Design Analysis Optimization Of Composite Wind Turbine Blade, Naishadh G. Vasjaliya
Fluid-Structure Interaction And Multidisciplinary Design Analysis Optimization Of Composite Wind Turbine Blade, Naishadh G. Vasjaliya
Doctoral Dissertations and Master's Theses
A multidisciplinary design analysis optimization (MDAO) process is defined for a composite wind turbine blade to optimize its aerodynamic and structural performance by developing a fluid-structural interaction (FSI) system. The objectives are to maximize aerodynamic efficiency and structural robustness while reducing blade mass and total cost. In the previous research, a MDO process of a composite wind turbine blade has been pioneered as an effective process to develop structurally optimized blade design. Present MDAO process is defined in conjunction with structural and aerodynamic performance of the blade which is divided into three steps and the design variables considered are related …
Characterizing A Co-Flow Nozzle For Use In A Filtered Rayleigh Scattering System, David S. Miceli
Characterizing A Co-Flow Nozzle For Use In A Filtered Rayleigh Scattering System, David S. Miceli
Theses and Dissertations
Research was conducted on the flow field exiting a co-annular flow nozzle for use in filtered Rayleigh scattering flow visualizations. More specifically, the flow visualizations were of the flow field exiting a coflow nozzle and illuminated by a tunable, nominal 4.2 watt narrow line width Argon laser operating at 514.5nm. ND:YAG lasers are typically used in this application, but some of the properties of a tunable Argon laser make it an attractive alternative. Before generating flow visualizations, the coflow nozzle was characterized both experimentally and computationally. Due to a flow asymmetry in the outer annulus flow field, the nozzle was …
Entropy Generation As A Means Of Examining Continuum Breakdown, Christopher R. Schrock
Entropy Generation As A Means Of Examining Continuum Breakdown, Christopher R. Schrock
Theses and Dissertations
To quantify the validity and breakdown of the continuum equations of fluid flow, the concept of entropy generation is examined. This parameter is formulated utilizing statistical mechanics and kinetic theory to avoid the use of equilibrium assumptions. This analysis leads to expressions in terms of energy distribution functions. These results are applied to monatomic and diatomic molecules. A numerical procedure for computing these values using the Direct Simulation Monte Carlo Method (DSMC) is presented. Normal shock waves in argon and nitrogen were simulated at Mach numbers ranging from 1.2 to 10. Results are compared to Navier-Stokes predictions. The Navier-Stokes equations …