Engineering Commons^™

Streaming Effects In Liquid Injection Rocket Engines With Transverse Mode Oscillations, Sean Robert Fischbach

Doctoral Dissertations

This research is an analytical investigation of wave interactions in a simulated liquid rocket engine with uniform injection imposed at the faceplate. Of significant interest are the secondary nonlinear flows, particularly acoustic streaming, induced by transverse wave impingement over the engine injector surface. The corresponding cylindrical chamber has a small length-to-diameter ratio with respect to solid and hybrid rockets. Given their low chamber aspect ratios, liquid thrust engines are known to experience severe tangential and radial oscillation modes more often than longitudinal ones. Experimental evidence demonstrates the production of large peak-to-trough amplitude flow oscillations along with the development of a …

Investigation Of The Sidewall Boundary Layers In The Bidirectional Vortex Liquid Rocket Engine, Joshua W. Batterson

Masters Theses

To complement previous studies on the bidirectional vortex, we attempt to characterize viscous effects in both the axial and radial directions along the sidewall with standard asymptotic techniques. The actual boundary layer present in the chamber will be a composite of both axial and tangential shearing layers. Since the tangential velocity is completely dominant, we expect the defining characteristics of the composite boundary layer to be congruent with the tangential layer in both thickness and axial invariance. The analytic analysis is outlined first by, the formulation of the boundary layer equations via Prandtl’s method. Next, asymptotic techniques are applied to …

Effects On Level Flight Performance Of The Optimized Wind Deflector Modification For The Md-500 Helicopter, Adam Joseph Cowan

Masters Theses

This thesis investigates the effects of personnel wind deflector devices on the level flight performance of an MD-500D helicopter configured with external passenger provisions. Numerous helicopter organizations operate with external passenger configurations. These configurations result in personnel exposure to high winds and an increase in parasite drag. Level flight performance is degraded by the increase in parasite drag caused by the external passengers. Wind deflectors were mounted on the forward portion of the fuselage to protect external passengers from the effects of wind exposure (high wind loads and wind chill factor) by deflecting the wind away from the fuselage. The …

A Study Of The Beginning Boundary Layer Influence On The Flow Field About A Two-Dimensional Automotive Model, Jonathan Gabriel Ford

Masters Theses

An experimental investigation was performed to analyze the beginning boundary layer produced on the floor of a subsonic wind tunnel and its influence on the flow field about a two-dimensional automotive model. Hot film anemometer measurements were taken in the test section of the wind tunnel operating under various inlet configurations. The use of a splitter plate and modifications to the contour of the inlet to the wind tunnel were then studied to find their affects on the height of the boundary layer in the wind tunnel test section. Finally, a 2-D automotive model was constructed with pressure taps along …

Investigation Of Non-Conventional Bio-Derived Fuels For Hybrid Rocket Motors, Scott Grayson Putnam

Doctoral Dissertations

Non-conventional bio-derived fuels have been evaluated for use in hybrid rocket motors. Tests were conducted at combustion pressures in the range of 100 – 220 psig and thrust levels of 40 – 170 newtons. Beeswax was tested with oxygen as the oxidizer and showed a regression rate at least three times as high as traditional hybrid propellant combinations such as hydroxyl-terminated polybutadiene (HTPB) and liquid oxygen (LOX). This provides the promise of a high thrust hybrid rocket motor using a simple, single port geometry and overcomes the main weakness of traditional hybrid rocket motor propellants, which are low regression rates. …

Active Vibration Control Using Optimized Piezoelectric Topologies, Matthew James Parsons

Masters Theses

This work investigates the optimal topology of an actively controlled piezoelectric actuator bonded to an elastic cantilever beam under steady-state harmonic loading near the first natural frequency of the beam. The actuator is discretized using finite elements, and control is applied to the actuator based on the sensor’s degrees of freedom using proportional control. This study investigates the optimal distribution of actuator material for one and five layers of finite elements. The optimized actuator topology shows substantial improvement over initial piezoelectric topologies and over traditional actuator placement. This study has two main topics, material homogenization and topology optimization. The piezoelectric …

Applying Human Factors Principles In Aviation Displays: A Transition From Analog To Digital Cockpit Displays In The Cp140 Aurora Aircraft, Ryan C. Palmer

Masters Theses

A flight test program that evaluated the results of a CP140 Aurora cockpit modernization project was conducted between May 2004 and October 2005. This paper uses the results of that test program to show how basic human factors principles were violated which led to the identification of multiple design deficiencies. This paper proposes that the failure to apply good human factors principles when designing aircraft displays can lead to unacceptable deficiencies. The result can be poor modal awareness, confusion in the cockpit, and often negative training for the pilots. In particular, four major deficiencies were analyzed to determine the specific …

A Dynamic Study Of An Earth Orbiting Tether Propulsion System, Stephen Edward Stasko

Doctoral Dissertations

Commercial expansion beyond Earth orbit demands efficient, low cost and regular access to space that is not given by current launch systems. An alternative to rocketry has been proposed in the use of tethers as a method of in-space propulsion. One possible implementation of tether propulsion involves the use of a long, vertically oriented tether orbiting the Earth. A suborbital launch vehicle will deliver a payload to the tether’s lower tip, which will then be carried up its length by an elevator car to the upper tip, where the payload is released on a transfer orbit. The orbiting space elevator …

How Airbus Surpassed Boeing: A Tale Of Two Competitors, William Alexander Burns

Masters Theses

Two of the most recognizable competitors in this new era of Euro-American competition are Airbus and Boeing. These two competitors are the world’s leading aircraft manufacturers and their competition is shaping the face of the commercial aviation industry. The competition between these two companies is for the “World’s Leading Commercial Airline Manufacturer.” This title is currently held by Airbus who has lead yearly production and taken more orders over the past three years.

Boeing has fallen behind in being the technological leader due to a falling budget, poor industrial model, and ethical practices. As a result of losing ground to …

The Design And Integration Of An Airborne Imager And Flight Campaign To Study The Time Evolution And Vertical Structures Of Polar Mesospheric Clouds, Jason David Reimuller

Masters Theses

The scientific objective of this study is to design an aircraft flight experiment that will provide airborne imaging data, augmenting satellite data, to advance the fundamental understanding of polar mesospheric clouds (PMCs). By capturing simultaneous top and bottom views of the PMCs, these airborne images will both provide insight into the time evolution of PMCs, and into the micro-features of these clouds, from which gravity waves and other details of the clouds vertical structures may be obtained. These data may help us better understand the driving mechanisms of these clouds and ultimately those elements of global climatic change, which are …

New Wings For The T-38: A Computational Performance Evaluation Of The T-38 Aircraft With A New Wing Design, John M. Kanuch

Masters Theses

Despite the recent improvements to the T-38 airframe and engines, the United States Air Force is still seeking ways to improve the aircraft’s takeoff, cruise, and landing performance. One potential way to improve the performance is to change the design of the wing. Using the Digital Performance Simulation aircraft-performance computer code, a T-38C performance evaluation sensitivity study was performed by parametrically varying the wing design. The computer model was a three degree of freedom, pointmass, batch simulation. The design changes investigated included varying aspect ratio with constant wing area, varying wing area with constant aspect ratio, and the addition of …

Pilot Vehicle Interface Improvements To The F/A-18 Weapon System (Using Human Factors Solutions To Increase Efficiency), Thomas B. Heck

Masters Theses

The purpose of this study was to evaluate and provide recommendations for optimizing the Pilot Vehicle Interface for components of data link systems employed on and currently in design for the F/A-18 Hornet and Super Hornet. Data was gathered using human factors research methodologies including descriptive studies, experimental research, and evaluation research. Additionally, flight and lab tests were used to gather data on systems that were mature enough in development. Overall, the study revealed that the interfaces for the systems evaluated could be modified in order to provide more situational awareness to the operator, allow for more logical display of …

Implementation Of The Acoustic Rapid Commercial-Off-The-Shelf Insertion Development Model In The P-3c Acoustic System, John Bruce Gailey Jr.

Masters Theses

The P-3C is a U.S. Navy aircraft designed for the Maritime Patrol and Reconnaissance mission. Although capable in a number of mission areas, the aircraft’s Anti-Submarine Warfare capabilities have received much attention lately due to improvements in diesel submarine technology. The acoustic systems on the P-3C needed a better way to more rapidly incorporate new technology while working within a constrained budget environment.

The purpose of this study is to show how the P-3C Acoustic System can be transformed by shifting from the slow, expensive traditional Military Specification (MILSPEC) development process to the successful Acoustic Rapid Commercial-Off-The-Shelf (COTS) Insertion (ARCI) …

Feasibility Of The Application Of The Maintenance Error Decision Aid Process To General Aviation Maintenance, Mark Thomas Blanks

Masters Theses

The purpose of this study was to determine the feasibility of applying the Maintenance Error Decision Aid (MEDA) that was developed by Boeing to general aviation maintenance shops, either in its current form or with limited modification. The MEDA investigation process has been implemented successfully by several major airlines and it was assumed that general aviation could also benefit from this safety enhancing process. Because of the nature of the MEDA process, this paper only addresses the feasibility of applying the MEDA process to large shops. After consulting aviation professionals and performing extensive research, a questionnaire was created and sent …

Nonlinear Behavior Of Longitudinal Waves In The Oscillations Of Rijke Tube, Nagini Devarakonda

Masters Theses

The Rijke tube device has been employed since its invention in 1859 in the experimental study of many examples of thermo-acoustic phenomena. The device exhibits generation of acoustic oscillations by heat energy supplied to the flow field in the fashion of a selfexcited oscillator. In recent times, the Rijke tube has proved to be a valuable tool in simulation of combustion instability phenomena in rockets and industrial burners. Despite the simplicity of the device, the Rijke tube simulates most important geometrical and physical features that lead to the growth of nonlinear pressure oscillations in combustion chambers. For example it provides …

Experimental Aerodynamic Analysis Of Converging Free Jets, Nathanael Tate Mcbee

Masters Theses

The setup of the converging jets is commonly used in the manufacture of meltblown fibers. This requires forced airflow through small channels angled toward each other until meeting at the exit of the die. The emerging air jets impinge while molten polymer is extruded and becomes entrained in the air flow to be collected downstream as a thin cooled fiber.

The experimental analysis of converging free jets was examined to reveal characteristics of the flow field. A hot-film anemometer was used to gather and analyze the corresponding data for two separate meltblown fiber dies. These were examined and compared to …

Lard Used As A Fuel For Hybrid Rocket Motors, Daniel Lee Pfeffer

Masters Theses

A bio-derived fuel, lard, was successfully tested using a laboratory scale hybrid rocket motor and a static test stand at the University of Tennessee-Knoxville. The experimental setup used gaseous oxygen as the oxidizer. Twenty-three experimental tests were successfully conducted with lard and oxygen. The nine-inch fuel grains used in the current investigation produced a measured thrust ranging from 70-145 Newtons (15-33 pounds) with calculated specific impulses ranging from 122-181 seconds. All the tests conducted were intensely fuel rich, and had equivalence ratios ranging from 0.2 to 0.45. The low equivalence ratios are partially due to unburned fuel particles that exit …

An Evaluation Of The Design Requirements Of The H-1 Upgrades Helicopter Blade Fold Racks, Matthew D. Funk

Masters Theses

The United States Marine Corps contracted Bell Helicopter Textron Inc. (BHTI) to develop and field new versions of the aging UH-1N and AH-1W helicopters. As part of the development effort of the H-1 Upgrades, BHTI was tasked with development of a folding rotor system and the associated equipment necessary to support main rotor folding operations. The blade fold equipment (BFE) was constrained throughout the development process by a list of conflicting requirements. The requirements for commonality, versatility, simplicity, light weight, rapid application, and durability, while each was generally reasonable, could not be satisfied with one set of equipment. The resulting …

A Compliance Strategy For Use Of Gps For Ifr Navigation In The E-2c Hawkeye, James Robert Mires

Masters Theses

Naval aviation is on the brink of taking advantage of a 12 year old capability. Naval commercial derivative aircraft have had the ability to navigate in instrument meteorological conditions using global positioning technology for nearly as long as civil commercial-for-hire aircraft. However, tactical naval aircraft, like the E-2C Hawkeye, are now only beginning to obtain and install the necessary technology to meet federal aviation regulations for satellite based area navigation.

Worldwide airspace controlling agencies have mandated the use of navigation equipment that meets highly specific performance standards prior to entry in required navigation performance airspace. Aircraft not compliant with these …

F/A-18a-D Hornet Current And Future Utilization Of Mode I Automatic Carrier Landings, Brian T. Schrum

Masters Theses

The purpose for writing this thesis is to prove the automatic carrier landing system (ACLS) a valuable Operational Risk Management (ORM) tool for recovering F/A-18A-D aircraft aboard the modern aircraft carrier. ORM is itself a subset of human factors and worthy of exploration in the aviation systems field. In proving the value of the ACLS, the author presents the following objectives: 1) describe the major components of the F/A-18A-D and modern aircraft carrier ACLS, 2) describe the current Mode I approach procedures, and the Precision Approach Landing Systems (PALS) certification process, 3) promote an increase in automatic landings during night …