High Strain Rate Dynamic Response Of Aluminum 6061 Micro Particles At Elevated Temperatures And Varying Oxide Thicknesses Of Substrate Surface, Carmine Taglienti

Masters Theses

Cold spray is a unique additive manufacturing process, where a large number of ductile metal micro particles are deposited to create new surface coatings or free-standing structures. Metallic particles are accelerated through a gas stream, reaching velocities of over 1 km/s. Accelerated particles experience a high-strain-rate microscopic ballistic collisions against a target substrate. Large amounts of kinetic energy results in extreme plastic deformation of the particles and substrate. Though the cold spray process has been in use for decades, the extreme material science behind the deformation of particles has not been well understood due to experimental difficulties arising from the …

Improving The Efficiency Of Wind Farm Turbines Using External Airfoils, Shujaut Bader

Masters Theses

Wind turbine efficiency typically focuses on the shape, orientation, or stiffness of the turbine blades. In this thesis, the focus is instead on using static fixed airfoils in proximity to the wind turbine to control the airflow coming out of the turbine. These control devices have three beneficial effects. (1) They gather air from “higher up” where the air is moving faster on average (and therefore has more kinetic energy in it). (2) They throw the used (and slowed down air) downwards. This means that any turbines in the wind farm behind the lead turbines do not get “stale” air. …

Modeling Dynamic Stall For A Free Vortex Wake Model Of A Floating Offshore Wind Turbine, Evan M. Gaertner

Masters Theses

Floating offshore wind turbines in deep waters offer significant advantages to onshore and near-shore wind turbines. However, due to the motion of floating platforms in response to wind and wave loading, the aerodynamics are substantially more complex. Traditional aerodynamic models and design codes do not adequately account for the floating platform dynamics to assess its effect on turbine loads and performance. Turbines must therefore be over designed due to loading uncertainty and are not fully optimized for their operating conditions. Previous research at the University of Massachusetts, Amherst developed the Wake Induced Dynamics Simulator, or WInDS, a free vortex wake …

New Generator Control Algorithms For Smart-Bladed Wind Turbines To Improve Power Capture In Below Rated Conditions, Bryce B. Aquino

Masters Theses

With wind turbines growing in size, operation and maintenance has become a more important area of research with the goal of making wind energy more profitable. Wind turbine blades are subjected to intense fluctuating loads that can cause significant damage over time. The need for advanced methods of alleviating blade loads to extend the lifespan of wind turbines has become more important as worldwide initiatives have called for a push in renewable energy. An area of research whose goal is to reduce the fatigue damage is smart rotor control. Smart bladed wind turbines have the ability to sense aerodynamic loads …

Kinetics Of Aluminization And Homogenization In Wrought H-X750 Nickel-Base Superalloy, Sean Reilly

Masters Theses

In sub-millimeter sheets of wrought H-X750 Nickel-base superalloy, aluminum-rich coatings are bonded to matrix with a vapor phase aluminization process. If an appropriate amount of aluminum is bonded to matrix with homogenization treatment, the resulting diffusion couple will diffuse into coherent (g/g’) heterogeneous phases creating matrix that is both precipitation and solid solution strengthened.

The diffusional mechanisms for solid solution mass transport involved with the growth and dispersion of bonded aluminum-rich coatings in the aluminization process only differ from the no external mass flow homogenization process with annealing treatment in that the boundary conditions are different. In each case these …