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Coal dust explosions can be hazardous; however, they can also generate a significant rise in stagnation pressure if adequately harnessed. Rotating detonation engine combustors seek to take advantage of the stagnation pressure rise phenomenon in a more sustained and controlled manner via confinement to a physical annulus, leading to increased overall thermodynamic efficiency. This investigation presents an analysis of detonations fueled by Carbon Black, a solid particulate consisting of virtually pure carbon molecules and lean Hydrogen-Air mixtures. As was previously realized with the addition of Carbon Black, an increase of operability limits and detonation velocities over that of a pure Hydrogen-Air interaction exist. For all testing conditions, the total equivalence ratio is held at f = 1, while the fuel mixture's carbon mass fraction is increased from 0 – 0.7. Total mass flow injected into the annulus remained constant (?0.415 kg/s). Detonation wave velocities are extracted from high-speed imaging through applying a Discrete Fourier Transform algorithm to determine changes to speed when Carbon Black particles are introduced. As a result, due to the addition of Carbon Black as an auxiliary fuel source, detonations were formed instead of deflagrations in operating conditions where one would expect deflagrations at the same Hydrogen-Air equivalence ratios without Carbon Black addition. The detonation formation provides evidence that the coal particles are reacting within the detonation wave in a large enough capacity to aid in forming and supporting a detonation wave within the annulus. The detonation wave velocities were found to decrease with hydrogen's incremental replacement with coal particles while maintaining a constant global equivalence ratio. Whereby, through a theoretical comparison of the heat of combustion as computed from the experimentally derived detonation wave velocities, a linear relationship of the two was shown to exist. Therefore, the heat of combustion has the potential to describe an operational limit to sustaining a detonation wave.

A solar sail is a space propulsion system that requires no onboard fuel source like traditional chemical fueled rockets. Instead, solar sails use solar pressure, which is utilized by the reflection and absorption of photons by the sail. This pressure is very small (9 N/km2 at 1 au from the sun). To take advantage of solar pressure, a solar sail must have a large surface area and a small mass. Despite these size and mass constraints, a solar sail has many benefits over other propulsion systems in certain applications. These benefits include a significantly reduced cost coupled with an increase in the allowable payload mass. Studying asteroids has many benefits as mankind increases its presence in space. Vesta in particular is worthy of studying because it is the most geologically diverse asteroid and we can learn many things from it. This thesis will show that a spacecraft using solar sails as the only propulsion source after sail deployment is well suited for a mission to study Vesta. Additionally, it will show the effectiveness of two commonly proposed methods for attitude stabilization of solar sail craft: gravity gradient and tip-mounted vanes.

The modem gas turbine engine is one of the most demanding operating environments in all of technology and has enabled the air transport industry to thrive. The highest efficiency levels are only obtainable by operating at temperatures that are well above the melting points of most materials inside the engine. Therefore, aggressive film cooling schemes and advanced materials enginee1ing are required to protect vulnerable surfaces from the hot jet streams inside a turbine. However, secondary flow effects in turbines and their interactions with these film cooling schemes are still not completely understood. To add to the body of knowledge in this area, a multi-purpose transonic annular cascade was designed to test, among other things, pressure losses across the cascade and endwall film cooling effectiveness both with and without the effects of a stator wake generator. Geometries were based off the first-stage rotors of the turbine of the General Electric Energy Efficient Engine (GE-E^3) a NASA-funded high-efficiency aviation engine developed in the late 1970s and early 1980s. This cascade geometry was impo1ted into a three-dimensional Computational Fluid Dynamics (CFD) program to obtain pressure and Mach number contour plots along various sections of interest in the cascade, for direct comparison to literature values and the GE-E3 reports. These initial CFD results compared favorably with literature values and suggest that the cascade design has high potential for use in the afore-mentioned experiments, though a more robust CFD analysis will be performed before a final decision is made.

A Linear Quadratic Regulator (LQR) [1] controller was designed with the objective of controlling a quad-rotor vehicle's vertical motion and angular rotations. When using this control algorithm, the quad-rotor vehicle would be able to stay in flight and only move with a constant vertical velocity, while being subjected to unmodeled dynamics and external disturbances. In order to accomplish this task, the quad-rotor system equations of motion were first derived and linearized, and a simulation was developed using Simulink 6.0. Using these linearized equations of motion, the LQR controller parameters were also obtained and the controller incorporated into the quadrotor simulation. Then, the testing conditions were varied in order to measure the performance of the controller. From the simulation results, as long as the changes from the vehicle's desired motion were kept relatively small, the controller worked well by controlling the desired four degrees of freedom and keeping the quad-rotor vehicle in its desired flight trajectory.

<p> Just over two decades ago the first planet outside our solar system was found, and thousands more have been discovered since. Nearly all these exoplanets were indirectly detected by sensing changes in their host stars' light. However, exoplanets must be directly imaged to determine their atmospheric compositions and the orbital parameters unavailable from only indirect detections. The main challenge of direct imaging is to observe stellar companions much fainter than the star and at small angular separations. Coronagraphy is one method of suppressing stellar diffraction to provide high star-to-planet contrast, but coronagraphs are extremely sensitive to quasi-static aberrations in the optical system. Active correction of the stellar wavefront is performed with deformable mirrors to recover high-contrast regions in the image. Estimation and control of the stellar electric field is performed iteratively in the camera's focal plane to avoid non-common path aberrations arising from a separate pupil sensor. Estimation can thus be quite time consuming because it requires several high-contrast intensity images per correction iteration.</p><p> This thesis focuses on efficient focal plane wavefront correction (FPWC) for coronagraphy. Time is a precious commodity for a space telescope, so there is a strong incentive to reduce the total exposure time required for focal plane wavefront estimation. Much of our work emphasizes faster, more robust estimation via Kalman filtering, which optimally combines prior data with new measurements. The other main contribution of this thesis is a paradigm shift in the use of estimation images. Time for FPWC has generally been considered to be lost overhead, but we demonstrate that estimation images can be used for the detection and characterization of exoplanets and disks. These science targets are incoherent with their host stars, so we developed and implemented an iterated extended Kalman filter (IEKF) for simultaneous estimation of the stellar electric field and the incoherent signal. From simulations and testbed experiments, we report the increased FPWC speed enabled by Kalman filtering and the use of the IEKF for exoplanet detection during FPWC. We discuss the relevance and future directions of this work for planned or proposed coronagraph missions.</p>

<p> Aerospace problems are characterized by strong coupling of different disciplines, such as fluid-structure interactions. There has been much research over the years on developing numerical solution methods tailored to each of the different disciplines. The classical approach to solving these strongly coupled systems is to stitch together these individual solvers by solving for one discipline and using the solution as boundary conditions for the successive disciplines. In more recent years, research has focused on numerical methods that handle solving coupled disciplines together. These methods offer the potential of better computational efficiency. These coupled solution methods range from monolithic solution strategies to decoupled partitioned strategies. This research develops a flexible finite element analysis tool which is capable of analyzing a range of aerospace problems including highly coupled incompressible fluid-structure interactions and turbulent compressible flows. The goal of this research is to access the viability of streamline-upwind Petrov-Galerkin (SUPG) finite element analysis for compressible turbulent flows. Additionally, this research uses a selection of nonlinear solution methods, linear solvers, iterative preconditioners, varying degrees of coupling, and coupling strategies to provide insight into the computational efficiency of these methods as they apply to turbulent compressible flows and incompressible fluid-structure interaction problems. The results suggest that SUPG finite element analysis for compressible flows may not be robust enough for optimization problems due to ill-conditioned matrices in the linear approximation. This research also shows that it is the degree of coupling and criticality of the coupling that drives the selection of the most efficient nonlinear and linear solution methods.</p>