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Articles 1 - 6 of 6

Full-Text Articles in Mechanical Engineering

Branch Detonation Of A Pulse Detonation Engine With Flash Vaporized Jp-8, John David Slack Dec 2006

Branch Detonation Of A Pulse Detonation Engine With Flash Vaporized Jp-8, John David Slack

Theses and Dissertations

Pulse Detonation Engines (PDE) operating on liquid hydrocarbon fuels are limited to operating frequencies of 35 Hz due to long ignition times from a low energy ignition sources. This study shows ignition time of JP-8 can be nearly eliminated by igniting a thrust tube using a secondary detonation. A counter flow heat exchanger attached to a thrust tube utilized waste heat from the detonation process to heat JP-8 to supercritical conditions. The fuel flash vaporized when injected into the air stream of the engine. A detonation was produced by a spark in a 5 cm diameter, 1.37 m long tube. …


Design And Numerical Simulation Of Two Dimensional Ultra Compact Combustor Model Sections For Experimental Observation Of Cavity-Vane Flow Interactions, David S. Moenter Sep 2006

Design And Numerical Simulation Of Two Dimensional Ultra Compact Combustor Model Sections For Experimental Observation Of Cavity-Vane Flow Interactions, David S. Moenter

Theses and Dissertations

An improved computational fluid dynamics (CFD) model was developed for numerical simulation of the Ultra Compact Combustor (UCC) concept to enhance turbulent flow characterization of the circumferentially traveling, centrifugal-force enhanced combustion, cavity flow into the engine main flow passage via a radial cavity in the turbine axial guide vanes. The CFD model uses a dense grid on a 60° periodic, axisymmetric combustor section, with the RNG κ-ε turbulence model to resolve turbulent flow details. An overall analysis and performance evaluation of the experimentally tested UCC configuration and an axially shortened cavity baseline configuration was conducted at various experimentally documented operating …


Inertia Measurement And Dynamic Stability Analysis Of A Radio-Controlled Joined-Wing Aircraft, William A. Mcclelland Mar 2006

Inertia Measurement And Dynamic Stability Analysis Of A Radio-Controlled Joined-Wing Aircraft, William A. Mcclelland

Theses and Dissertations

Dynamic stability and stall during steady level turns were examined for VA-1, a joined-wing flight demonstrator aircraft. Configurations with a lower vertical tail and fairings over the main landing gear were compared with a recommendation on the combination had the best drag and dynamic stability characteristics. The dynamic stability analysis was broken into four key parts: a twist test experimentally measured mass moments of inertia, a panel method was used to find non-dimensional stability derivatives, lateral and longitudinal state space models estimated dynamic stability characteristics and handling quality levels were evaluated using a Cooper-Harper based rating system. VA-1 was found …


Design, Build And Validation Of A Small-Scale Combustion Chamber Testing Facility, Eric R. Dittman Mar 2006

Design, Build And Validation Of A Small-Scale Combustion Chamber Testing Facility, Eric R. Dittman

Theses and Dissertations

This study investigated the design parameters necessary for the construction and use of a testing facility built to test the combustor section of engines. User inputs were acquired by interview and used in the decisions made in arrangement of pieces of machinery and how different systems were to interact. The design was then carried out as the various parts of the facility were built and installed. Software was designed which controlled the different parts of the combustion process and monitored the different products of combustion as well as the properties of the air and fuel used in the combustion. These …


Optimization Of A Low Heat Load Turbine Nozzle Guide Vane, Jamie J. Johnson Mar 2006

Optimization Of A Low Heat Load Turbine Nozzle Guide Vane, Jamie J. Johnson

Theses and Dissertations

Often turbomachinery airfoils are designed with aerodynamic performance foremost in mind rather than component durability. However, future aircraft systems require ever increasing levels of gas-turbine inlet temperature causing the durability and reliability of turbine components to be an ever more important design concern. As a result, the need to provide improved heat transfer prediction and optimization methods presents itself. Here, an effort to design an airfoil with minimized heat load is reported. First, a Reynolds-Averaged Navier-Stokes (RANS) flow solver was validated over different flow regimes as well as varying boundary conditions against extensive data available in literature published by the …


Alleviation Of Buffet-Induced Vibration Using Piezoelectric Actuators, Shawn D. Morganstern Mar 2006

Alleviation Of Buffet-Induced Vibration Using Piezoelectric Actuators, Shawn D. Morganstern

Theses and Dissertations

Buffet-induced vibration has been problematic for aircraft structures for many years. The F-16 ventral fin, while prone to these effects, lends itself well to the evaluation of modern active structural and flow control technologies. The objective of this research was to determine the most critical natural modes of vibration for the F-16 ventral fin and design piezoelectric actuators capable of reducing buffet-induced ventral fin vibration. A finite element model (FEM) for the fin was developed, tuned and optimized to closely match published modal frequencies. Piezoelectric actuator patches were designed using the strain characteristics of the FEM and integrated into the …