Mechanical Engineering Commons^™

Simulating The Effects Of Floating Platforms, Tilted Rotors, And Breaking Waves For Offshore Wind Turbines, Hannah Johlas

Doctoral Dissertations

Offshore wind energy is a rapidly expanding source of renewable energy worldwide, but many aspects of offshore wind turbine behavior are still poorly understood and are not accurately captured by low-cost engineering models used in the design process. To help improve these models, computational fluid dynamics (CFD) can provide valuable insight into the complex fluid flows that affect offshore wind turbine power generation and structural loads. This research uses CFD simulations to examine three main topics important to future offshore wind development: how breaking waves affect structural loads for fixed-bottom wind turbines; how platform motions affect power generation, wake characteristics, …

Optimization Of Mixing In A Simulated Biomass Bed Reactor With A Center Feeding Tube, Michael T. Blatnik

Masters Theses 1911 - February 2014

Producing gasoline-type fuels from lignocellulosic biomass has two advantages over producing alcohol-type fuels from plant sugars: gasoline has superior fuel characteristics and plant lignin/cellulose does not compete with human food supplies. A promising technology for converting lignocellulose to fuel is catalytic fast pyrolysis (CFP). The process involves injecting finely ground biomass into a fluidized bed reactor (FBR) at high temperatures, which reduce the biomass to gases that react inside the catalyst particles. This entails complex hydrodynamics to efficiently mix a stream of biomass into a catalyst bed that is fluidized by a separate stream of inert gas. Understanding the hydrodynamics …

Multidimensional Modeling Of Condensing Two-Phase Ejector Flow, Michael F. Colarossi

Masters Theses 1911 - February 2014

Condensing ejectors utilize the beneficial thermodynamics of condensation to produce an exiting static pressure that can be in excess of either entering static pressure. The phase change process is driven by both turbulent mixing and interphase heat transfer. Semi-empirical models can be used in conjunction with computational fluid dynamics (CFD) to gain some understanding of how condensing ejectors should be designed and operated.

The current work describes the construction of a multidimensional simulation capability built around an Eulerian pseudo-fluid approach. The transport equations for mass and momentum treat the two phases as a continuous mixture. The fluid is treated as …