Engineering Commons^™

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 …

Turbulent Transition In Electromagnetically Levitated Liquid Metal Droplets, Jie Zhao

Masters Theses

The condition of fluid flow has been proven to have a significant influence on a wide variety of material processes. In electromagnetic levitation (EML) experiments, the internal flow is driven primarily by electromagnetic forces. In 1-g, the positioning forces are very strong and the internal flows are turbulent. To reduce the flows driven by the levitation field, experiments may be performed in reduced gravity and parabolic flights experiments have been adopted as the support in advance. Tracer particles on the surface of levitated droplets in EML experiment performed by SUPOS have been used to investigate the transition from laminar to …

Hybrid Rocket Design Study Utilizing Nozzle Cooling And Aft-End Vortex Oxidizer Injection, John Nicholas Quigley

Masters Theses

The current study focused on two innovations intended to reduce the cost and enhance the performance of hybrid rockets. The majority of the emphasis was placed on the design, fabrication and testing of a 3-D printed, water cooled nozzle. This work was done as proof of concept to show that complex, high temperature components could be manufactured using these new techniques, thereby substantially bringing down fabrication costs and allowing configurations that are not feasible using traditional machining. A water-cooled calorimeter nozzle was made and used in thrust stand tests to verify analytic and numerical heating models used in the design …

A Qualitative Experimental Study Of Drag Reduction Devices For Tractor Trailers With Ground Effects, Nicolas Robert Reed

Masters Theses

This is an experimental qualitative study of how drag reduction devices affect air flow around a tractor trailer. A 1/32 scale detail model of a truck with its trailer was used for testing in a 20"x14" low speed wind tunnel at the University of Tennessee Space Institute. Major modifications were made to the wind tunnel so that it would include a moving bed (floor) section for ground effect simulation. This was done to accurately simulate relative ground movement with the truck being held stationary in the tunnel flow.

Drag reduction devices were designed based on aerodynamic fundamental understanding for streamlining …

Neutron Imaging Of Lithium (Li) Coolants Inside High Temperature Niobium (Nb) Heat Pipes, Brad Harrison Hight

Masters Theses

Lithium (Li) behavior inside a high temperature Nb-Li leading edge heat pipe was successfully imaged under induction heating operation via neutron imaging. Startup and cool-down operations gave visual confirmation of bulk Li movement using both gravity assisted and inverted operating orientations. The pipe was imaged during an operation cycle from ambient conditions, heated to a steady state temperature of 908.8 ⁰C, and allowed to cool below 200^°C. The experiment was performed at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, and at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee.

Tomographic images …