Digital Commons Network^™

Cooling Of Qps Modular Coils Using Embedded Copper Tubes, Shankar Narasimhaswami

Masters Theses

In an era of insatiable appetite for energy, mankind is challenged to develop a sustainable, safe and clean means of energy production, which would virtually eliminate the existing dependence on fossil fuels. In this regard, Nuclear Fusion technology would give man a quantum leap to mark a near end to the long-term energy concerns and redefine the basis of energy production on earth and elsewhere. This explanation holds rationale on two principal elements 1-Abundant supply of cheap fusion fuel and 2-Surpassingly superior energy production efficiency.

But, as every boon comes with a ‘But’, the criticality of technology is that fusion …

Investigation Of Knock In Gaseous Fuels In The Presence Of Diluents, Roshan Ashok Rodrigues

Masters Theses

Recent energy security and environmental concerns have prompted growing interest into utilization of alternative fuels such as, natural gas and landfill gas. These gaseous fuels contain significant amount of diluents in the fuel composition, such as carbon dioxide, nitrogen, water vapor and other trace gases, which vary by geographical location. Successful engine operation is limited by a phenomenon called "knock", which occurs due to auto-ignition of the end gas ahead of the flame front, and therefore, needs to be investigated with the utilization of these gaseous fuels.

The present contribution discusses the experimental set-up, procedure and results of the investigation …

A Parametric Study Of Water Vapor Condensation In Supersonic Nozzle Flow Fields, Todd Branson Vanpelt

Masters Theses

Combustion driven hypersonic and supersonic wind tunnels are impaired in their flight simulation abilities by the condensation of water vapor introduced into the test stream by the burning byproducts of air and hydrocarbon fuels. The purpose of this study is to evaluate the abilities of a condensation model to predict the beginning axial locations of vapor changing into liquid droplets and study the correlations with initial combustion chamber conditions. A test matrix with different fuels, chamber pressure, and equivalence ratio was applied to the FIRACON model written by Erickson, et al. [7] using the dimensions of the NASA Langley …

Accelerated Poisoning Of Diesel Oxidation Catalysts By Zinc Dialkyldithiophosphate-Derived Phosphorus, Scott Joseph Eaton

Masters Theses

The phosphorus poisoning of diesel oxidation catalysts (DOCs) by the lube-oil additive zinc dialkyldithiophosphate (ZDDP) is investigated in the present study. A 517 cc single-cylinder, naturally aspirated direct-injection diesel engine is used to accelerate the phosphorus poisoning of DOCs by artificially increasing the ZDDP consumption to approximately 700 times of that found during normal engine operation. Three methods of accelerating the ZDDP consumption rate are investigated, which have been shown in previous literature to cause phosphorus poisoning. These include the injection of high concentration ZDDP-doped lube-oil blended with diesel fuel though the fuel injector as well as injecting ZDDP-doped lube-oil …

Selection Of Attractor Sounds For An Audio-Based Navigation System For The Visually Impaired, Brad Salisbury

Masters Theses

Research in to human hearing has been very ‘laboratory’ oriented in the sense that the test environments do not replicate most ‘real world’ situations [J.C. Middlebrooks and D.M. Green, Ann. Rev. of Psychology, 42, 135-159 (1991)]. While very useful information is gained from these types of tests, it is difficult to see how ‘real world’ situations affect sound source localization, recognition, and navigation (walking/way finding) performance. Such information is especially important to people who are visually impaired and dependent on prior knowledge of the environment or audio cues for travel. The research reported here was conducted during the development of …

Flow And Heat Transfer In A 2-D Channel Partially Filled With Porous Medium, Srinivas Kuppa

Masters Theses

Graphite foam, developed by the Oak Ridge National Laboratory, has shown excellent thermal properties and has potential applications for compact heat exchangers. The flow and heat transfer characteristics of a 2-D channel partially filled with graphite foam as the porous medium are determined. A steady, incompressible and constant-property water flow is modeled using the commercial software COMSOL^â. Flow is uniform at the inlet and the base of the foam is subjected to a constant heat flux boundary condition. The permeability( 7x10^-8 to 1.4x10^-6 m²)and the dimensionless height of the porous block are varied. Heat …

Modal Analysis Of A Helicopter Wing-Pylon Structure Using Flexible Multibody Dynamics, Naresh Nilkanth Khude

Masters Theses

With the new software tools being developed for simulation of flexible multibody systems it is possible to develop the models with various missiles and launchers and study their dynamic behavior in the design stages. In most of the flexible multibody models, the flexibility modal data is obtained from the corresponding detailed finite element model.

This thesis presents the flexible multibody model development of the simplified wing- pylon structure using the Craig-Bampton approach. Since the Craig-Bampton method of Component Mode Synthesis is used, the component finite element models are developed separately without inclusion of the local joint details. This approach is …

Characterizing Monolithic Lean Nox Trap Catalysts Using A Bench-Flow Reactor, Hakyong Kim

Masters Theses

The performance of EmeraChem Lean NO_x Trap (LNT) catalysts with company proprietary washcoat formulation has been investigated using a bench-flow reactor (BFR). The washcoat composition consists of Pt, the precious metal component (PM), and two NO_x storage media of Ba and K, supported on g-Al₂O₃ washcoat.

A series of isothermal absorption experiments was carried out at different temperatures and gas hourly space velocities (GHSVs) in order to investigate the effect of temperature and GHSV on the nitrogen oxides (NO_x) trapping capacity of EmeraChem LNT catalysts. The NO_x storage capacity exhibits a “volcano-type” …

Landfill Gas As A Fuel For Ic Engine Operations, Guruprasath Narayanan

Masters Theses

An alternative fuel research facility was developed to study different alternative gaseous fuels like Landfill gases and Biogases and their mixtures with hydrogen as a fuel in a single cylinder spark ignition engine. Landfill gas was used as a fuel and the optimum process parameters such as compression ratio, spark timing and equivalence ratio were identified and reported.

Hydrogen enhanced combustion of landfill gas was studied and it was found that the addition of small amounts of hydrogen in the land fill gas has improved the combustion characteristics of the fuel and the performance of the spark ignition engine in …

First And Second Law Analyses Of Conventional And Advanced Combustion Modes, Christopher Robert Hamilton

Masters Theses

The objective of this paper was to perform first and second law analyses of conventional and advanced combustion modes. The data to be analyzed came from two computer models. The first model simulated a modified Mercedes diesel engine operating in the conventional mode, and the second simulated operation in the advanced combustion mode.

Each model was constructed using geometric measurements from the experimental engine setup. Experimental data were used to correlate the output from the models with that of the actual engine. Once each model was deemed valid, its output was subjected to a first and second law analysis.

In …

Design Of A Single Axle Regenerative Brake System For A 2005 Thru-The-Road Hybrid Electric Chevrolet Equinox, John William Miller

Masters Theses

The University of Tennessee through its mechanical engineering department is participating in an advanced vehicle design competition, Challenge X, sponsored by the Department of Energy and General Motors. Participants are challenged with redesigning a 2005 Chevrolet Equinox that will minimize energy consumption and reduce emissions while maintaining the stock performance, safety, and utility of the vehicle. The overall vehicle architecture and control system for Tennessee's vehicle entry is described while focus is given to the design of the single axle series regenerative braking system. A series regenerative braking system provides a means of capturing the kinetic energy otherwise lost in …

Modeling Of Tapered Corrugated Graphite-Foam Heat Exchangers, Abdoulaye Sy

Masters Theses

Practical applications of compact heat exchangers, using low-permeability (1.4e-10 m²) high-conductivity (150 W/m-K) graphite-foam for heat transfer enhancement, are often limited by the excessive pressure-drop.

In an earlier study, Norton (2003), using straight-cut corrugations through the entire height of the graphite-foam heat exchanger, identified minimal pressure-drop configurations. For these optimal configurations, pressure-drop reductions of nearly two orders of magnitude were achieved when compared to a full block of graphite foam. With a constant heat flux (12 W/cm²) boundary, the high thermal conductivity of the foam has resulted in heat transfer values that are two orders of …

Grasping Strategies For A Dexterous Hand During Teleoperation, Prem Sagar Chidambaram

Masters Theses

Telerobotics is an interdisciplinary branch of engineering that deals with the control of robots at a distance in a manner that entails the intuition and the physical involvement of the operator controlling the robot. The end of the robotic manipulator consists of a device called an end effector that is used to hold the tools. Most telerobotic systems employ a simple single degree of freedom end effector called a parallel jaw gripper. Since such end effectors have just one degree of freedom and hence limited dexterity, it is essential to develop special fixtures to be attached to the tool …

Design Of A Catalyst System With Periodic Flow Reversal For Lean Burn Natural Gas Engines, Balaji Ramamurthy

Masters Theses

The objective of this research is to accomplish methane conversion from lean burn natural gas engines. As methane conversion requires high temperatures, the concept of PFR (Periodic Flow Reversal) is used. The PFR is a heat trap that performs active heat recovery in addition to the heat retention capability of monolith solids. Cyclically alternating the direction of exhaust flow produces a thermal wave along the center of the catalyst thereby elevating the temperature above the engine exhaust temperature. The PFR loop is developed connecting catalyst canisters with a Four-Way Single Diversion Valve (FWSDV) using a set of pipes and pipe …

Numerical Simulations On Machining Of Silicon Carbide, Jerry Jacob

Masters Theses

Experiments were conducted to determine the critical depth of cut for machining of single crystal silicon carbide through Single Point Diamond Turning (SPDT) and fly-cutting, and of CVD coated Silicon Carbide through scratching. The ductile nature of these nominally hard and brittle materials is believed to be the result of a high pressure phase transformation, which generates a plastic zone of material that behaves in a metallic manner. The SPDT experiments have shown chip formation similar to that in metal machining. This metallic behavior is the basis for using AdvantEdge, metal machining simulation software, for comparison to experimental results. The …

Analytical Modeling And Simulation Of An Auv With Five Control Surfaces, John Tomasi

Masters Theses

This research describes the dynamic modeling and numerical simulation of an autonomous underwater vehicle (AUV) with five hydrodynamic control surfaces, necessary for the development of an autopilot algorithm, based solely upon analytical methodologies. The purpose of this research was to demonstrate the ability to develop a low. order approximation of the dynamics and control characteristics of an underwater vehicle that is complete enough to validate a specific design before physical construction begins; therefore, allowing for a more cost effective virtual design, test, and evaluation process. The AUV model developed in this study takes into consideration inertia, hydrostatic forces, hydrodynamic forces, …

Computational Simulation Of Turbulent Forced Convection Flow Over A Horizontal Plate Heater In A Rectangular Channel, Bhagavathi Perumal Natarajan

Masters Theses

The phenomenon of turbulent forced convection in the entry region of a rectangular duct was investigated computationally using commercial CFD software, FLUENT. The Standard k-ε turbulence model from FLUENT was used to model turbulence in the 20mm high x 30mm wide cross-sectional rectangular duct. The operating fluid used for the three-dimensional CFD study was water at an inlet temperature of 90° C, with the velocities ranging from 0.5 m/s to 2 m/s, at 1 atm pressure. A constant heat flux was applied to the base of the rectangular channel with the other flow walls insulated. The heat flux ranged from …

Comparison Of Combustion Sources And Measurement Techniques For Particulates Emitted From Engines And A Power Plant, Matthew F. Chandler

Masters Theses

"Sub-micron particulates emitted from various combustion sources have serious negative impacts on human health and the environment. It is essential to accurately characterize the physical properties of these particulates including size, shape, structure, and chemical composition in order to monitor, regulate, and model the various transport, toxic, optical, chemical, and deposition properties which dictate their harmful effects. This study consists of two related investigations involving the application of diagnostics methods to characterization and comparison of combustion generated particulate emissions from various sources. The first investigation includes the measurement of particulates emitted from a compression-ignition (diesel) engine using two independent measurement …