Lift generating technologies are often considered a potential solution to increased power generation and reliability within wind turbine design. The Sprayed Liquid Flap (SLF) is a novel active control method that has shown success in providing lift generation on aircraft wings, but its application in the context of rotating flows is unexplored. This research aims to understand the effects of the SLF on a wind turbine and provide a pathway for future exploration of its aerodynamic impacts on rotating flows. Computational Fluid Dynamics with an Euler-Euler multiphase approach is employed to assess the influence of the SLF on a wind turbine's power generation capabilities. With the need for multiphase physics comes increased computational cost which poses a challenge for future research into the rotational multiphase flows. The Blade Element Momentum Method (BEM) provides an elegant, proven solution for estimating rotating flows for cheap so to aid in future works, the efficacy of BEM as an estimator for multiphase rotating flows will be explored through a SLF equipped wind turbine. The current findings indicate that the SLF equipped wind turbine exhibits power benefits over a conventional turbine. In addition, they suggest that BEM could serve as a reasonable estimator for the exploration of rotational multiphase physics.

Ignition systems within scramjet combust ors remain a trending topic of research because of the essential role they play in the engine's operation. An alternative to currently researched ignition systems is investigated in this study with the main goal of u tilizing the same liquid fuel as the mai n combustion chamber for the ignition system itself. In this case, JetA fuel was injected in a liquid jet in crossflow configuration with air to atomize the fuel. To characterize this ignition system, metrics such as combustion chamber pressure rise, pulse frequency, and jet penetration were used to validate possible utilization within a scramjet combustor. Tests were completed at different air temperatures ranging from 150C to 275C, varying spark plug frequencies, and at two unique combustion chamber exi t diameters. Schlieren imaging was also used to compare effects of temperature and exit nozzle diameter on jet quality. Results obtained demonstrate a high pressure rise, reliable ignition, and a fine jet exhaust fro m the combustion chamber. To increase pu lse frequency a more optimized combustion chamber is required along with a fuel injection system that would atomize the liquid fuel better than the current system. Following studies include further testing within a s upersonic flow regime to simulate the fl ow effects experienced within a scramjet combustion chamber. If results continue to prove useful , the current technology studied has the ability to innovate supersonic combustion engines by reducing mass from the flight vehicle and increasing reliability, both critical parameters.

This study investigates the utilization of computational fluid dynamics (CFD) to simulate aerodynamic heating effects in support of research and design endeavors. The initial investigation demonstrates the effectiveness of a computational approach in analyzing different geometries and flow conditions. Specifically, CFD is employed to analyze the aerodynamics of a blunt cone, double cone, and hypersonic leading edge experiencing a changing heat source across the flow/body boundary. At the stagnation point, maximum thermal loading occurs as previously found; therefore, boundary layer thickness and shock standoff distance is measured at that position to compare the results of each case. Characteristics such as temperature and pressure reveal shock and boundary layer distance and how the heat flux shifts the layers away from the body as its added into flow, and narrows the regions as the flow is cooled. For the more complex geometry of the double cone, two shocks are seen in adiabatic flow, but increasing heat flux into the flow pushes the shock layer further from the body until the shocks merge, causing drag reduction across the body; simulating an ablative heat shield that is burning. Overall, designs of a simpler nature are less influenced by heat flux, but more complex designs and regions demand considering heat flux, or even use it to an aerodynamic design advantage.

Characterizing temperature fields and species evolution inside explosive fireballs is crucial for providing constraints for model refinement and extending the current understanding of detonation afterburn chemistry. Nitromethane is of interest due to its wide variety of automotive, industrial, and military applications, including as a propellant for rockets. This effort looked to provide accurate characterization of temperature and species evolution inside of a fireball using laser absorption spectroscopy techniques. Recent advances in laser absorption spectroscopy are leveraged to make MHz-rate measurements of temperature and species concentration following the detonation of nitromethane in a controlled environment. A Fixed-Wavelength Tunable Diode Laser Absorption Spectrometer (FW-TDLAS) was developed and characterized before being interfaced with the AFRL's detonation afterburn test facility. Laser diagnostics offer many advantages over traditional measurements techniques such as being non-intrusive and allowing for time-resolved measurements of temperature and multiple species. H2O was targeted at two wavelengths in the mid-infrared to quantify the localized temporal evolution of species and temperature inside the fireball and afterburn of nitromethane. Additional diagnostics were added to allow for CO species evolution to be targeted and resolved as well.

Previous research has identified a potential link between microgravity conditions and the onset of osteoporosis, a connection that stems from altered fluidic pathways crucial in nutrient dispersion and cell stimulation. Specifically, the absence of mechanical loading in space environments reduces fluid shear stress, thereby disrupting the normal flow of interstitial fluid in trabecular bone. This disruption greatly impacts the functionality of osteoblasts and osteoclasts, the vital cells responsible for maintaining healthy bones. The focus of this study aims to explore the impact of microgravity on bone loss in astronauts, establishing the connection between the lack of mechanical loading and the reduction of fluid shear stress. Computational Fluid Dynamics (CFD) techniques are used to analyze the behavior of the interstitial fluid in the trabecular bone and the transportation of nutrients in the trabecular system. Key parameters, such as permeability and wall shear stress were examined to understand their influence on nutrient distribution. Results indicate a considerable reduction in wall shear stress in both healthy and osteoporotic bones under microgravity conditions. Higher wall shear stresses are observed in healthy bones under normal gravitational conditions, solidifying the connection between cellular stimulation and the development of osteoporosis. Additionally, a Peclet number was computed using experimental data to simulate the characteristics of interstitial fluid, indicating a significant reliance on mechanically driven flow for nutrient dispersion. The current observations not only provide valuable insights into the physiological transformations astronauts undergo in space, but also highlight the potential of CFD techniques as a powerful tool for modeling complex fluid flow within trabecular bone, paving the way for diverse biological applications.

Ignition delay times from undiluted mixtures of natural gas (NG)/H2/Air and NG/NH3/Air were measured using a high-pressure shock tube at the University of Central Florida. The combustion temperatures were experimentally tested between 1000-1500 K near a constant pressure of 25 bar. Mixtures were kept undiluted to replicate the same chemistry pathways seen in gas turbine combustion chambers. Recorded combustion pressures exceeded 200 bar due to the large energy release, hence why these were performed at the high-pressure shock tube facility. The data is compared to the predictions of the NUIGMech 1.1 mechanism for chemical kinetic model validation and refinement. An exceptional agreement was shown for stoichiometric conditions in all cases but strayed at lean and rich equivalence ratios, especially in the lower temperature regime of H2 addition and all temperature ranges of the baseline NG mixture. Hydrogen addition also decreased ignition delay times by nearly 90%, while NH3 fuel addition made no noticeable difference in ignition delay time. NG/NH3 exhibited similar chemistry to pure NG under the same conditions, which is shown in a sensitivity analysis, demonstrating hydrogen chemistry to be dominant in NG/H2 mixtures and hydrocarbon chemistry to be dominant in NG/NH3 mixtures. The reaction CH3 + O2 = CH3O + O is identified and suggested as a possible modification target to improve model performance. Increasing the robustness of chemical kinetic models via experimental validation will directly aid in designing next-generation combustion chambers for use in gas turbines, which in turn will greatly lower global emissions and reduce greenhouse effects.

There is a growing need for a fundamental understanding of how detonations are formed and sustained as propulsion technology advances toward the use of detonation-based engines. The deflagration-to-detonation transition (DDT) phenomenon is studied to better understand both the fundamentals of detonation physics and the conditions surrounding how detonations are formed and sustained. This research aims to study the effects of a wedge on DDT and detonation formation. A hydrogen-air mixture is pumped into a chamber and ignited by a spark plug. Turbulence-driven flame acceleration is induced by turbulators in the chamber through which the flame propagates. The flame then flows over and interacts with a wedge in a test section, which has quartz windows for viewing. Schlieren and chemiluminescence imaging are used to collect data from the test section. The contact of the wedge with the reacting flow creates reflected shocks that interact with and accelerate the flame front. It is also shown that DDT is repeatedly induced across from the wedge.

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