Diesel-Like And Hcci-Like Operation Of A Truck Engine Converted To Hydrogen, Alberto A. Boretti

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In addition to the traditional spark ignition (SI), premixed, gasoline-like and compression ignition (CI), diffusion, Diesel-like operation of internal combustion engines, premixed, homogeneous charge, compression ignition (HCCI) operation has also been proposed to improve the fuel conversion efficiency and reduce the pollutant formation. to be attractive, the operation in HCCI mode has to be coupled with the other traditional operations, being HCCI in general difficult to be controlled and limited to values of the air-to-fuel equivalence ratio λ within a narrow windows set by the lean burn limits with large λ and the peak pressure limits with small λ. Furthermore, …

Formulation Of An Optimal Search Strategy For Space Debris At Geo, Daniel J. Jackson

Master's Theses

The purpose of this thesis is to create a search strategy to find orbital debris when the object fails to appear in the sky at its predicted location. This project is for NASA Johnson Space Center Orbital Debris Program Office through the MODEST (Michigan Orbital Debris Survey Telescope) program. This thesis will build upon the research already done by James Biehl in “Formulation of a Search Strategy for Space Debris at GEO.” MODEST tracks objects at a specific right ascension and declination. A circular orbit assumption is then used to predict the location of the object at a later time. …

Implementation And Validation Of The Ζ-F And Asbm Turbulence Models, Dustin Van Blaricom Quint

Master's Theses

The use of Computational Fluid Dynamics (CFD) tools throughout the engineering industry has become standard. Simulations are used during nearly all steps throughout the life cycle of products including design, production, and testing. Due to their wide range of use, industrial CFD codes are becoming more flexible and easier to use. These commercial codes require robustness, reliability, and efficiency. Consequently, linear eddy viscosity models (LEVM) are used to model turbulence for an increasing number of flow types. LEVM such as k-ε and k-ω provide modeling with little loss of computational efficiency and have proven to be robust. The LEVM that …

A Look At Near-Term Nuclear Fission And Fusion Rockets For Human Mars Missions, Douglass W. Casey

Von Braun Symposium Student Posters

No abstract provided.

Analysis Of Plasma Jet Driven Magneto-Inertial Fusion As Potential Primary Propulsion Driver For Project Icarus, Milos Stanic

Von Braun Symposium Student Posters

No abstract provided.

A Comparison Of Pulsed And Steady-State Reactor Operation For A Fusion Rocket, Althea Wilson

Von Braun Symposium Student Posters

No abstract provided.

File Sensor Optimization, Josiah Thomas

Von Braun Symposium Student Posters

No abstract provided.

Projected Velocity And Efficiency Trends For A Pulsed Fusion Magnetic Nozzle, Lloyd M. Jackson

Von Braun Symposium Student Posters

No abstract provided.

Hüpla Vlf Lightning Detector: Hopes, Dreams, & Duct Tape, K Coates, D Everding, N Kaifler, P Kühl, R Puestow

Von Braun Symposium Student Posters

No abstract provided.

Firefly--Fusion-Powered Interstellar Rendezvous And Exploratory Flying Laboratory, Mitchell Rodriguez

Von Braun Symposium Student Posters

No abstract provided.

Rapid Settlement Architecture“Pebble Station”, Joshua M. Brock

Von Braun Symposium Student Posters

No abstract provided.

Balloonsat As A Platform For Deploying The Neutron Counter, Mark Becnel

Von Braun Symposium Student Posters

No abstract provided.

Magnetic Field Mapping In The Plasmoid Thruster Experiment (Ptx), Coby W. Mccolgin

Von Braun Symposium Student Posters

No abstract provided.

Libra The Airborne Launch-Pad, Lucas Schoukroun, Amandine Delahaye

Von Braun Symposium Student Posters

No abstract provided.

Current Sheet Structures From Ace And Messenger Observations, Lorin Arnold, Gang Li

Von Braun Symposium Student Posters

No abstract provided.

The Case For An L1 Space Station For Stellar Missions, Wade Harlow

Von Braun Symposium Student Posters

No abstract provided.

A Probabilistic Design Analysis Approach In Reducing The Overall Risk Of A Fusion Propulsion Spacecraft, Natalie Walker

Von Braun Symposium Student Posters

No abstract provided.

Student Launch Initiative: Boosted Dart Rocket, Charger Rocket Works

Von Braun Symposium Student Posters

No abstract provided.

Plasma Jet Magneto Inertial Fusion Thruster Concept, Richard Hatcher

Von Braun Symposium Student Posters

No abstract provided.

Beamed Energy For Ablative Propulsion In Near Earth Space, Grant Bergstue

Von Braun Symposium Student Posters

No abstract provided.

Design And Development Of An Advanced Thermonuclear Fusion Propulsion R&D Facility At Uahuntsville, Ross J. Cortez

Von Braun Symposium Student Posters

No abstract provided.

Direct Numerical Simulation Of Hypersonic Turbulent Boundary Layers. Part 4. Effect Of High Enthalpy, L. (Lian) Duan, M. P. Martín

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper we present direct numerical simulations (DNS) of hypersonic turbulent boundary layers to study high-enthalpy effects. We study high-and low-enthalpy conditions, which are representative of those in hypersonic flight and ground-based facilities, respectively. We find that high-enthalpy boundary layers closely resemble those at low enthalpy. Many of the scaling relations for low-enthalpy flows, such as van-Driest transformation for the mean velocity, Morkovin's scaling, and the modified strong Reynolds analogy hold or can be generalized for high-enthalpy flows by removing the calorically perfect-gas assumption. We propose a generalized form of the modified Crocco relation, which relates the mean temperature …

Considerations For Numerical Modeling Of Inverted Wings In Ground Effects, Graham Doig, Tracie J. Barber

Aerospace Engineering

No abstract provided.

Performance Analysis Of A Variable Conductance Heat Pipe, Herron Arreola

Aerospace Engineering

This report examines the analysis of a donated Boeing variable conductance heat pipe with unknown performance characteristics. These characteristics were found through experimental means by utilizing 14 thermocouples attached to various locations on the heat pipe, the heaters and to the insulation. Although the maximum axial heat transport capability could not be determined due to the limited number of strip heaters available, the maximum radial heat flux capability of the heat pipe was found to be 2.46 W/in². The experiment also revealed that increasing the input power decreased the burn out inclination angle and that using a coolant …

Constrained Hermite Tls For Mesh-Free Derivative Estimation Near And On Boundaries, Robert A. Mcdonald, Alejandro Ramos

Aerospace Engineering

A Taylor series least-squares approach to estimating derivatives on scattered data is extended to include derivative observation or specification. This approach allows improved estimation of derivatives near boundaries as compared with the standard ghost node approach. It also enables a unique method of estimating derivatives in a surface using only surface data.

A Multi-Regulator Sliding Mode Control Strategy For Output-Constrained Systems, Hanz Richter

Mechanical Engineering Faculty Publications

This paper proposes a multi-regulator control scheme for single-input systems, where the setpoint of a regulated output must be changed under the constraint that a set of minimum-phase outputs remain within prescribed bounds. The strategy is based on a max–min selector system frequently used in the aerospace field. The regulators used for the regulated and limited outputs are of the sliding mode type, where the sliding variable is defined as the difference between an output and its allowable limit. The paper establishes overall asymptotic stability, as well as invariance properties leading to limit protection. The design methodology is illustrated with …

Mars Carbon Dioxide Propulsion, Christopher Cushman Perry

Mechanical & Aerospace Engineering Theses & Dissertations

An experimental investigation was conducted to characterize the performance of a small-scale supersonic propulsion system using supercritical CO₂ as a propellant intended for Mars surface applications. This research has focused on estimating the specific impulse behavior of high-pressure carbon dioxide propellant that can be produced by condensing dry ice out of Mars's atmosphere and heating it at constant volume to temperatures above its 31.1 ° C critical temperature. Since supercritical fluid was created by heating different dry ice-vapor mixtures to moderate temperatures, the nominal initial density and thermodynamic state within the pressure vessel could be controlled. The instrumented test …

Study Of The Role Of Pressure Relaxation In Inviscid, Incompressible Flows, Jonathan Strzelec

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis has investigated the role of pressure relaxation in inviscid, incompressible flows. A modified form of the classical Bernoulli equation was developed from a vector form of the Navier-Stokes equation which includes pressure relaxation and bulk viscosity. This modified Bernoulli equation was utilized to compare two-dimensional potential flow pressure distributions over a sphere, cylinder, backward and forward facing steps. Finally, the modified Bernoulli equation was utilized to compare the theoretical bounding free streamline to an experimentally observed free streamline over a knife edge. Results of these comparisons show that the classical form of the Bernoulli equation can over-predict the …

Effective Approach For Estimating Turbulence-Chemistry Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, M. P. Martín

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An effective approach for estimating turbulence-chemistry interaction in hypersonic turbulent boundary layers is proposed, based on "laminar- chemistry" Reynolds-averaged Navier-Stokes mean flow solutions. The approach combines an assumed probability density function with a temperature fluctuation scaling, which provides the second moment for specifying the shape of the probability density function. As a result, the effects of temperature fluctuation on chemical production rates can be estimated without solving an additional moment evolution equation. The validity of this method is demonstrated using direct-numerical-simulation data. This approach can be used to identify regions with potentially significant turbulence-chemistry interaction in hypersonic boundary layers and …

State Of The Art Of Piloted Electric Airplanes, Nasa's Centennial Challenge Data And Fundamental Design Implications, Lori Anne Costello

Doctoral Dissertations and Master's Theses

The purpose of this study was to determine the current state of the electric airplane as primarily defined by results from NASA's Green Flight Challenge Competition. New equations must be derived in order to determine the endurance and range for electric airplanes since the standard equations depend upon weight change over a flight and the weight of an electric airplane does not change. These new equations could then be solved for the optimal velocity and altitude which were the two driving factors that could change range and endurance for a given airplane configuration. The best velocity for range and endurance …