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Papers by W Ethan Lick Eagle

SAE International Journal of Engines, 2017

International audienc

SAE Technical Paper Series, 2015

Journal of Fluid Mechanics, 2014

The interaction between two separated flow regions was studied for the fundamental problem of a s... more The interaction between two separated flow regions was studied for the fundamental problem of a shock wave–boundary layer interaction (SBLI) within a rectangular inlet. One motivation is that the inlet of an engine on a supersonic aircraft may contain separation zones on the sidewalls and the bottom wall; if one region separates first it can alter the flow on the other wall and lead to engine unstart. In our work an oblique shock wave was generated by a wedge suspended from the upper wall of a Mach 2.75 wind tunnel. Stereo particle image velocimetry (PIV) measurements were recorded in 25 planes that include all three possible orthogonal orientations. The lateral velocity and vorticity measurements help to explain the underlying flow structure and these quantities were not measured previously for this problem. It is concluded that the sidewall and bottom wall separation zones interact due to an underlying flow structure that is similar to the two types of 3-D separation patterns prev...

40th Fluid Dynamics Conference and Exhibit, 2010

Mixed compression inlets offer a great increase in pressure recovery compared to conventional ext... more Mixed compression inlets offer a great increase in pressure recovery compared to conventional external compression inlets at Mach numbers above two. These inlets suffer from problems with shock wave boundary layer interactions (SBLI) which cause flow instabilities and severe performance reductions. Previous experiments conducted at the University of Michigan used a wind tunnel with glass side walls with an extensive test section to measure the SBLI associated with a single oblique shock. This work presents a redesign of the single oblique shock experimental setup, using computational fluid dynamics, to also include a downstream normal shock with a diffuser. The new experimental configuration will provide insights into the effects that combined oblique/normal shock boundary layer interactions have on the health of the boundary layer in the diffuser section of a mixed compression inlet. The extensive glass walls of the wind tunnel will allow direct access for optical measurements of the shock boundary layer interactions and the diffuser section. Nomenclature AIP = Aerodynamic Interface Plane CFD = Computational Fluid Dynamics NSH = Normal Shock Holder k = Turbulent Kinetic Energy M = Mach number M ∞ = Inflow Mach number OSG = Oblique Shock Generator SBLI = Shock wave boundary layer interaction

49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2011

In a rectangular supersonic inlet the first oblique shock wave will interact with both the sidewa... more In a rectangular supersonic inlet the first oblique shock wave will interact with both the sidewall boundary layers and with the corner flows. This can create large, complex 3-D separation zones that reduce the effective flow area and can lead to the unstart of the inlet. Experiments were conducted in the Michigan Glass Wind Tunnel at Mach 2.75 and at Mach 2.0 to quantify these flow separation patterns. Video was recorded of the unsteady formation of separation zones as the inlet starts. Oil streak patterns and Schlieren images indicate that the downward flow caused by the oblique shock forces some of the flow near the corner to move upstream. This flow moving upstream in the corner creates a sidewall separation bubble, which significantly deflects the free stream upstream of the shock wave. Using a six-degree wedge, a "small" corner flow-shock boundary layer interaction (CF-SBLI) separated region was created which was found to be optimum for CFD simulation. Using a ten-degree wedge generated a stronger shock and a "large" CF-SBLI separated region, but the flow area was reduced so much that the inlet was too close to unstart to allow for stable experimental measurements or CFD simulation.

44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 2008

The past ten years have seen a rapid increase in interest in high specific impulse thrusters whic... more The past ten years have seen a rapid increase in interest in high specific impulse thrusters which can deliver very high payload mass fractions compared to chemical thrusters. One such choice, the Hall thruster, is gaining ground due to its relative simplicity and commercial availability. In order to accomplish high impulse missions however, these low thrust devices must successfully operate for thousands of hours. To help offset the enormous cost of extended ground testing, a variety of modeling efforts is underway. The goal of this paper is to overview the past and present of Hall thruster model development and to highlight three areas of research: improved sputtering models, uniform availability of magnetic field data and anomalously high electron mobility, which have each individually shown promise towards improving the predictive capability of these modeling efforts.

52nd Aerospace Sciences Meeting, 2014

combustioninstitute.org

... Eric Bumbalougha, W. Ethan Eaglea, and Margaret Wooldridgea,b ... References [1] I. Atribak, ... more ... Eric Bumbalougha, W. Ethan Eaglea, and Margaret Wooldridgea,b ... References [1] I. Atribak, FE López-Suárez, A. Bueno-López, and A. Garcıa-Garcıa, “New insights into the performance of ceria-zirconia mixed oxides as soot combustion catalysts. ...

Journal of Propulsion and Power, 2013

ABSTRACT Aluminum is an attractive energy storage material for underwater propulsion because of i... more ABSTRACT Aluminum is an attractive energy storage material for underwater propulsion because of its high density and strongly exothermic reaction with seawater. However, the degree to which an aluminum–seawater power system could outperform other systems has remained unknown because of uncertainties about volume and energy costs associated with the balance of plant. This work addresses this problem by developing a thermodynamic model for a complete Rankine-cycle propulsion system based on the aluminum–seawater reaction and combining this with a scaling methodology for inferring the system’s effective energy density.The results show that replacing battery-based power systems with aluminum combustion based ones could increase range/endurance by factors of four to ten over competing technologies. Overall system efficiency is maximized by adjusting the water mass flow to fuel mass flow ratio so as to control the temperature and quantity of steam. Although increasing the amount of combustion byproduct, hydrogen, improves the performance of the turbine, the thermodynamic cost of compressing the hydrogen can be very high.As a result, developing a compact device for achieving an isothermal compression of waste hydrogen is necessary to fully realize the energy density advantage of the aluminum fuel.

Fuel, 2014

Reliable prediction of spray penetration and spray break-up is required to achieve increases in f... more Reliable prediction of spray penetration and spray break-up is required to achieve increases in fuel efficiency and reduction of emissions in diesel engines. Of particular interest is the early transientflow regime. In the current work, diesel fuel spray development was studied using high-speed imaging of a high-pressure diesel common-rail fuel injector mounted in a spherical constant volume combustion chamber. The fuel injector nozzle had four holes aligned on a radial plane with diameters of 90, 110, 130, and 150 µm. Fuel was injected into a room temperature T = 298 K (±1.5%), nitrogen environment at chamber densities of 17.5, 24.2, and 32.7 kg/m 3 (±3%) and for fuel-rail pressures of 1000, 1500, and 2000 bar (±1.5%). Images of the backlit fuel injection were captured at 100,000 frames per second. Image processing algorithms were used to determine fuel spray penetration distance and maximum penetration rate as a function of time. The experimental results for maximum penetration rate and transition time are compared with various quasi-one-dimensional fuel-spray models. The experimental results show departure from the model predictions at higher chamber densities and injection pressures at early times in the spray development. Furthermore, the spray penetration data show 2-dimensional spray geometry changes at early times. A fuel spray tip tracking algorithm was developed to show the maximum penetration distance does not occur along the jet center-line during the transient period of injection and to quantify the angular location of the maximum penetration distance. The data provide valuable insights into transient fuel spray behavior and guide the development of the next generation of spray theory and models.

Bulletin of the American Physical Society, Oct 6, 2012

Advancement in the understanding of state of charge and efficiency requires better coupling of ba... more Advancement in the understanding of state of charge and efficiency requires better coupling of battery level properties with the micro-structure of the constituents. The composition of the target synthesis material, lithium manganese oxide ($ Li Mn_2 O_4 $, or LMO for short) is known to impact lithium ion battery properties. Following this motivation, our aim is to demonstrate control over the microstructure and compositional properties of LMO using parameters of the combustion synthesis environment. In this experiment, one or both solid ...

New experimental results are presented of a three dimensional inlet shock-boundary layer interact... more New experimental results are presented of a three dimensional inlet shock-boundary layer interaction (3DI-SBLI) generated by a six-degree full-span wedge installed in the 57$ times $70-mm Michigan'Glass Inlet'wind tunnel at Mach 2.75. Images from two traditional techniques, oil flow and Schlieren are compared. Oil flow lines, coincident with the local skin friction, show a complex three dimensional picture despite the two-dimensionality of the density gradient visualization. Analytical complexity regarding three dimensional flow has ...

This thesis presents a thermodynamic analysis of a novel Rankine cycle aluminum/steam combustion ... more This thesis presents a thermodynamic analysis of a novel Rankine cycle aluminum/steam combustion power system being developed for use in Unmanned Underwater Vehicles (UUVs). The analysis is performed using a system modeling tool developed by the NASA Glenn Research Center called Numerical Propulsion System Solver (NPSS). Thermodynamic models of the individual components are created and linked together in NPSS, which then solves the system by enforcing mass and energy conservation. Design and off-design conditions are simulated and predicted performance is compared with predictions made by two other research groups. The simulations predict that this power system could provide at least five-fold increases in range and endurance for the US Navy's 'Sea Horse' UUV. A rudimentary sensitivity analysis is used to identify the factors which most strongly influence the performance of the design. Lastly, recommendations for future work and possible model improvements are discussed.