Engineering Commons^™

Jet Engine Thrust Ratings, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

A Method To Generate Pressure Gradients For Molecular Simulation Of Pressure-Driven Flows In Nanochannels, Zhi Liang, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

One of the Difficulties in Molecular Simulation of Pressure-Driven Fluid Flow in Nanochannels is to Find an Appropriate Pressure Control Method. When Periodic Boundary Conditions (PBCs) Are Applied, a Gravity-Like Field Has Been Widely Used to Replace Actual Pressure Gradients. the Gravity-Fed Method is Not Only Artificial, But Not Adequate for Studying Properties of Fluid Systems Which Are Essentially Inhomogeneous in the Flow Direction. in This Paper, a Method is Proposed Which Can Generate Any Desired Pressure Difference to Drive the Fluid Flow by Attaching a "Pump" to the Nanofluidic System, While the Model is Still Compatible with PBCs. the …

Stochastic Reactor Modelling Of Multi Modes Combustion With Diesel Direct Injection Or Hydrogen Jet Ignition Start Of Combustion, Alberto A. Boretti

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Recent papers [1-5] have proposed two different systems to more efficiently and more rapidly burn the fuel in highly boosted, high compression ratio, directly injected internal combustion engines permitting multi-mode combustion operation. in a first system, a second direct injector is coupled with the standard Diesel direct injector and glow plug. the second direct injector introduces most of the fuel while the Diesel direct injector only introduces a minimum amount of fuel to control the start of the combustion about top dead center. the fuel injected before the Diesel ignition injection burns premixed, the fuel injected after the Diesel ignition …

Optimal Slewing Of A Constrained Telescope Using Seventh Order Polynomial Input Torques, Julia K. Bush

Master's Theses

Two-axis gimbals are frequently used to point cameras and telescopes at various points of interest for surveillance, science, and art. The rotation of a two-axis gimbal system is governed by nonlinear angular momentum equations of motion. This paper presents a method for slewing a telescope in space with a gimbaled sensor attached to a nominally non-rotating spacecraft using two seventh order polynomial input functions to characterize torques. To accomplish this task, picking the optimal coefficients of the seventh order polynomial was necessary. It was also desired to use constraint equations to limit the excursion, angular velocity, angular acceleration, and jerk …

Freedrop Testing And Cfd Simulation Of Ice Models From A Cavity Into Supersonic Flow, Thomas J. Flora

Theses and Dissertations

Weapon release at supersonic speeds from an internal bay is highly advantageous. For this reason, both experimental and numerical methods were used to investigate store separation from a cavity (L=D=4.5) into Mach 2.94 flow. The experiment used a piezoresistive pressure transducer, Schlieren and high-speed photography for data acquisition. The computational solution used the OVERFLOW solver. A sphere and a Mk-82, scaled to 1:20, were formed using frozen tap water. The sphere model was freedrop tested experimentally and computationally, while the sub-scale store shaped model was freedrop tested experimentally. The total pressure was varied to alter the dynamic response of the …

Analysis Of A Goldschmied Propulsor Using Computational Fluid Dynamics Referencing California Polytechnic's Goldschmied Propulsor Testing, Cory A. Seubert

Master's Theses

The Goldschmied Propulsor is a concept that was introduced in mid 1950's by Fabio Goldschmied. The concept combines boundary layer suction and boundary layer ingestion technologies to reduce drag and increase propulsor efficiency. The most recent testing, done in 1982, left questions concerning the validity of the results. To answer these questions a 38.5in Goldschmied Propulsor was constructed and tested in Cal Poly's 3x4ft wind tunnel. The focus of their wind tunnel investigation was to replicate Goldschmied's original testing and increase the knowledge base on the subject. The goal of this research was to create a computational fluid dynamics (CFD) …

An Alternative Dual-Launch Architecture For A Crewed Asteroid Mission, Steven M. Korn

Master's Theses

This thesis is a feasibility study for a crewed mission to a Near Earth Asteroid (NEA). An alternate dual-launch architecture is proposed and analyzed against a more established architecture. Instead of a rendezvous in a low-Earth parking orbit, the new architecture performs the rendezvous while the two spacecraft are on an Earth-escape trajectory to the destination NEA. After selecting a target asteroid, 2000 SG344, each architecture will have its best mission compared to the best mission of the other architecture.

Using the new architecture, a mission is created to the chosen NEA, 2000 SG344. A back-up Orion MPCV and a …

The New Bicycle Model: Introducing Software Considerations Early Into The Systems Engineering Design And Integration Process, Nathaniel Dinglasan Angat

Master's Theses

Lockheed Martin Space Systems Company, Sunnyvale, California is in the business of designing and engineering satellites for commercial and government customers. This task is by no means a trivial endeavor but Lockheed MartinSunnyvale has many decades of experience in Systems Engineering. Training in systems engineering is a long process whose training tools must be kept up-to-date and appropriate as new advances in technology evolve along-side with the processes that develop these ever-evolving solutions. For many years new systems engineers have been introduced to the Bicycle Model as a paradigm for designing and developing complex systems that are composed of diverse …

Genetic Algorithm Optimization Of A Film Cooling Array On A Modern Turbine Inlet Vane, Jamie J. Johnson

Theses and Dissertations

In response to the need for more advanced gas turbine cooling design methods that factor in the 3-D flowfield and heat transfer characteristics, this study involves the computational optimization of a pressure side film cooling array on a modern turbine inlet vane. Latin hypersquare sampling, genetic algorithm reproduction, and Reynolds-Averaged Navier Stokes (RANS) computational fluid dynamics (CFD) as an evaluation step are used to assess a total of 1,800 film cooling designs over 13 generations. The process was efficient due to the Leo CFD code's ability to estimate cooling mass flux at surface grid cells using a transpiration boundary condition, …

Effects Of Front-Loading And Stagger Angle On Endwall Losses Of High Lift Low Pressure Turbine Vanes, M. Eric Lyall

Theses and Dissertations

Past efforts to reduce the airfoil count in low pressure turbines have produced high lift profiles with unacceptably high endwall loss. The purpose of the current work is to suggest alternative approaches for reducing endwall losses. The effects of the fluid mechanics and high lift profile geometry are considered. Mixing effects of the mean flow and turbulence fields are decoupled to show that mean flow shear in the endwall wake is negligible compared to turbulent shear, indicating that turbulence dissipation is the primary cause of total pressure loss. The mean endwall flow field does influence total pressure loss by causing …

Where Did All Those Launches Come From? Or What Can We Do Now That We Have Launches?, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Where did all those Launches come from? Or What can we do now that we have launches?" from August 11, 2012.

Telescope Assembly Alignment Simulator Performance Optimization, Joshua G. Thompson, Brian Eney, Zaheer Ali, Bob Thompson

STAR Program Research Presentations

The Telescope Assembly Alignment Simulator (TAAS) calibrates scientific instruments (SI’s) that are installed on the Stratospheric Observatory For Infrared Astronomy (SOFIA). An SI’s accuracy is directly dependent on the consistent performance of the TAAS, which has never been fully characterized. After designing various thermal and optical experiments to identify the current unknowns of TAAS, we now have a far better grasp on how the equipment behaves.

Two-Stage, High-Altitude Rocket With Internal Skeleton Design Entered In Advance Category Of 7th Esra Irec, Samuel S. Bowman, Kevin J. Byrne, Allen Capatina, Aliki S. Loper-Leddy, Joshua A. Van Schoyck

Aerospace Engineering

A high-altitude, two-stage rocket was designed, built, and entered in the advanced category of the 7^th Annual Experimental Sounding Rocket Association (ESRA) Intercollegiate Rocketry Engineering Competition (IREC). The rocket, called AJAKS, featured an internal skeleton made of carbon fiber rods, and a combination of plywood, carbon, and aluminum bulkheads. Loads were driven through the internal structure, with an outer skin tube providing an aerodynamic surface. A unique separation device was developed to ensure proper stage separation. The competition required the rocket to carry a 10-lb payload, which was chosen by the team to consist of an IMU and data …

Control System Development For Small Uav Gimbal, Nicholas J. Brake

Master's Theses

The design process of unmanned ISR systems has typically driven in the direction of increasing system mass to increase stabilization performance and imagery quality. However, through the use of new sensor and processor technology high performance stabilization feedback is being made available for control on new small and low mass stabilized platforms that can be placed on small UAVs. This project develops and implements a LOS stabilization controller design, typically seen on larger gimbals, onto a new small stabilized gimbal, the Tigereye, and demonstrates the application on several small UAV aircraft. The Tigereye gimbal is a new 2lb, 2-axis, gimbal …

A Resistance Based Structural Health Monitoring System For Composite Structure Applications, Dennis N. Boettcher

Master's Theses

This research effort explored the possibility of using interwoven conductive and nonconductive fibers in a composite laminate for structural health monitoring (SHM). Traditional SHM systems utilize fiber optics, piezoelectrics, or detect defects by nondestructive test methods by use of sonar graphs or x-rays. However, these approaches are often expensive, time consuming and complicated.

The primary objective of this research was to apply a resistance based method of structural health monitoring to a composite structure to determine structural integrity and presence of defects.

The conductive properties of fiber such as carbon, copper, or constantan - a copper-nickel alloy - can be …

The Effect Of A Low-Velocity Impact On The Flexural Strength And Dynamic Response Of Composite Sandwiches With Damage Arrestment Devices, Kodi A. Rider

Master's Theses

Impact strength is one of the most important structural properties for a designer to consider, but is often the most difficult to quantify or measure. A constant concern in the field of composites is the effect of foreign object impact damage because it is often undetectable by visual inspection. An impact can create interlaminar damage that often results in severe reductions in strength and instability of the structure. The main objective of this study is to determine the effectiveness of a damage arrestment device (DAD) on the mechanical behavior of composite sandwiches, following a low-velocity impact. A 7.56-lb_f crosshead …

An Experimental Investigation Of A Goldschmied Propulsor, Joshua Roepke

Master's Theses

A wind tunnel investigation of an axisymmetric bluff body, known as a Goldschmied propulsor, was completed. This model conceptually combines boundary layer control and boundary layer ingestion into a single complementary system that is intended to use energy to reduce the axial force on the body by eliminating separation and increasing the pressure recovery aft of the body’s maximum thickness. The goal of the current project was to design, fabricate, and fully document the performance of a wind tunnel model incorporating the Goldschmied propulsor concept and complete an examination of its aerodynamic performance. The investigation took place at California Polytechnic …

Computational Analysis Of A Wing Oscillator, Ryne Derrick Radermacher

Masters Theses

An analysis of a newly proposed wind power extraction device called a wing oscillator was performed using computational fluid dynamics (CFD). A wing oscillator is a device that consists of two airfoils attached to a central pivot by means of a frame or shaft. Oscillatory motion is produced by controlling the angle of attack of the airfoils as a fluid flow is passed over the device. A robust mathematical scheme was developed to investigate the performance of the wing oscillator and was hooked to the CFD software package FLUENT through User Defined Functions (UDFs). Using the dynamic meshing analysis methods …

Waste Heat Utilization In An Anaerobic Digestion System, Brett Boissevain

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Anaerobic digestion has great potential as an energy source. Not only does it provide an effective method for waste mitigation, but it has the potential to generate significant quantities of fuel and electricity. In order to ensure efficient digestion and biomass utilization, however, the system must be continuously maintained at elevated temperatures. It is technically feasible to supplement such a system with outside energy, but it is more cost effective to heat the system using only the produced biogas. While there is considerable literature covering the theory of anaerobic digestion, there are very few practical studies to show how heat …

Design Of A Split Hopkinson Bar Apparatus For Use With Fiber Reinforced Composite Materials, Shawn Michael Lang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tabulated material properties are the starting block for the design of most structures. Mechanical structures undergo a wide range of loading conditions. Structures can be loaded statically or dynamically with a wide range of strain rates. With impact loading or high strain rates the relationships between stress and strain are not the same as in static loading. It has been observed that material properties are dependent upon the rate at which they are tested. Many investigators have studied the effect of high compressive strain rate loading conditions, in metals. The most common method for determining the dynamic response of materials …

Numerical And Experimental Study Of Anisotropic Effective Thermal Conductivity Of Particle Beds Under Uniaxial Compression, Jingwen Mo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Planetary heat flow is of great interests to planetary scientists, which can be used to determine the history and current status of pianetary bodies. Thermal conductivities of planetary bodies are generally measured using long needle-like probes inserted into planet's surface, which measure the horizontal effective thermal conductivity (parallel to the planetary surface). The vertical effective thermal conductivity (perpendicular to the planetary surface), used for heat flow calculation, is assumed to be the same as the horizontal effective thermal conductivity. However, ETC of particle beds is known to be an anisotropic property under low compressive pressures.

The objective of this study …

Experimental Studies Of Vertical Mixing In An Open Channel Raceway For Algae Biofuel Production, Ram Sudheer Voleti

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The USU BioEnergy Center has been successful in developing algae feedstocks for renewable biofuels and bioproducts. The concept is to utilize and maximize algae feedstocks for liquid transportation fuels, biomass for burning and digestion, and high value co-products. It is theorized that increasing the mixing in open and closed algal production systems improves the productivity of the algae culture. A raceway cultivation system was chosen to examine the phenomena of mixing. Vertical mixing will provide more uniform exposure to sunlight for all of the algae in the raceway. The main focus of this research was to increase vertical mixing. Delta …

Flexible Circuits For Aerospace Applications With Special Emphasis On Rf Connectors, Abhishek Nareshraj Singh

Graduate Theses and Dissertations

The current work focused on the study of flexible electronic circuits for use in aerospace applications with emphasis on RF Connectors. The electrical and mechanical performance of the flexible circuits was studied and compared to a standard coaxial cable for feasibility study in avionics space. Also, Anisotropic Conductive Films (ACF) are studied for connecting the flexible RF connectors and their performance studied for electrical and mechanical behavior with change in bonding parameters.

High-Throughput Rear-Surface Drilling Of Microchannels In Glass Based On Electron Dynamics Control Using Femtosecond Pulse Trains, Lan Jiang, Pengjun Liu, Xueliang Yan, Ni Leng, Chuancai Xu, Hai Xiao, Yongfeng Lu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This study proposes a rear-surface ablation enhancement approach to fabricate high-aspect-ratio microchannels by temporally shaping femtosecond laser pulse trains. in the case study of K9 glass, enhancements of up to a 56 times higher material removal rate and a three times greater maximum drilling depth are obtained by the proposed method, as compared with conventional femtosecond laser drilling at the same processing parameters. the improvements are due to the changes of photon-electron interactions by shaping femtosecond pulse train, which can effectively adjust the photon absorption and localized transient material properties by changing electron dynamics such as free electron densities. © …

Tiny Satellites For Stem, Carlos G. Niederstrasser

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Carlos G. Niederstrasser titled "Tiny Satellites for STEM" from July 13, 2012.

Efficient Airframe Management Using In-Situ Structural Health Monitoring, Mark M. Derriso, M. S. Leonard, Martin P. Desimio, Steven E. Olson

Student Publications

The United States Air Force utilizes the Aircraft Structural Integrity Program (ASIP) to service and maintain its airframes. This schedule-based maintenance approach works well for ensuring system integrity; however, it is very costly, labor-intensive, and it reduces system availability. As a result, the Air Force intends to transition to a process that services aircraft based on their actual condition instead of the presumptive schedule-based approach. Structural health monitoring (SHM) technologies are being investigated to enable such real-time state awareness and decision-making. This paper provides a brief review of ASIP and the required inspections to investigate structural fatigue. The current ASIP …

Potential Significance Of Photoexcited No2 On Global Air Quality With The Nmmb/Bsc Chemical Transport Model, O. Jorba, D. Dabdub, Christopher S. Blaszczak-Boxe, C. Pérez, Z. Janjic, J. M. Baldasano, M. Spada, A. Badia, M. Gonçalves

Publications and Research

Atmospheric chemists have recently focused on the relevance of the NO2* + H2O → OH + HONO reaction to local air quality. This chemistry has been considered not relevant for the troposphere from known reaction rates until nowadays. New experiments suggested a rate constant of 1.7 × 10−13 cm3 molecule−1 s−1, which is an order of magnitude faster than the previously estimated upper limit of 1.2 × 10−14 cm3 molecule−1 s−1, determined by Crowley and Carl (1997). Using the new global model, NMMB/BSC Chemical Transport Model (NMMB/BSC-CTM), simulations are presented that assess the potential significance of this chemistry on global …

Merrill-Cazier Library Gas Exhibition, Betty Rozum, Andrew Wesolek, Pamela N. Martin

Education and Outreach

This exhibition, presented in the Merrill-Cazier Library, captured the history and accomplishments of the GAS program. Click the download button to see a PowerPoint presentation featuring images and text from the exhibition.

Hot-Wire Anemometer For The Boundary Layer Data System, William D. Neumeister

Master's Theses

Hot-wire anemometry has been routinely employed for laboratory measurements of turbulence for decades. This thesis presents a hot-wire anemometer suitable for use with the Boundary Layer Data System (BLDS). BLDS provides a unique platform for in- flight measurements because of its small, self-contained, robust design and flexible architecture. Addition of a hot-wire anemometer would provide BLDS with a sensor that could directly measure flow velocity fluctuations caused by turbulence. Hot-wires are commonly operated in constant-temperature mode for high frequency response, but require a carefully tuned bridge. The constant-voltage anemometer (CVA) uses a simple op-amp circuit to improve frequency response over …

Modeling, Identification, Validation And Control Of A Hybrid Maglev Ball System, Ahmed Elhussein E. Mekky

Mechanical & Aerospace Engineering Theses & Dissertations

In this thesis, the electrodynamics of a single axis hybrid electromagnetic suspension Maglev system was modeled and validated by applying it to a single axis hybrid maglev ball experiment. By exploring its linearized model, it was shown that the single axis hybrid Maglev ball has inherently unstable dynamics. Three control scenarios were explored based on the linearized model; (1) Proportional, Deferential (PD) control, (2) Proportional, Deferential, Integral (PID) and (3) PID controller with pre-filtering. This thesis has shown that a PID controller with a pre-filtering technique can stabilize such a system and provide a well-controlled response.

A parametric system identification …