Engineering Commons^™

Synthesis And Characterization Of Metal-Based Reactive Powders, Yasmine Aly

Dissertations

Aluminum added to propellants, explosives, and pyrotechnics, boosts their energy density. Different approaches were investigated that could shorten aluminum ignition delays, increase combustion rates, and decrease the tendency of aluminum droplets to agglomerate. Here, Al-based reactive, mechanically milled materials are prepared and characterized.

For powders with Fe, Ni, or Zn additives, the particles consist of an aluminum matrix and inclusions of Fe, Ni, or Zn comprising 10 at % of the bulk composition. For additives of Ni and Zn, only short milling times can be used to prepare composites; intermetallic phases form at longer milling times. Thermogravimetric analysis shows selective …

Laboratory Apparatus For Gas Turbine Combustion Development, Dustin Lee Cruise

Open Access Theses

The next generation of combustor technology will be required to meet the demands of a world more focused on greenhouse gases and global warming. Due to this new focus on emission control, combustors must produce less NO x , while operating in a higher pressure environment that is more prone to combustion instabilities.

This work focuses on the development of a lab and combustor that will be used for the next generation combustor development. The lab development includes layout and organization, facilities, measurement and instrumentation, automation of the testing process, and an imaging tool for diagnostics.

A Lean Direction Injection …

Quantitative Imaging Of Radiation Intensity From A Turbulent Sooting Flame, Robert Kapaku

Open Access Theses

Quantitative imaging of radiation intensity (QIRI) is a method of investigating temporally and spatially resolved radiation from species and particulates in turbulent flames. The current study reports quantitative images of radiation intensity from a turbulent ethylene flame that matches the Reynolds number (15,200) of a non-sooting flame from the International Workshop on Measurement and Computation of Turbulent Non-premixed Flames. A calibrated high-speed infrared camera with four band-pass filters was used to acquire images of radiation intensity in wavelengths corresponding to carbon dioxide, water vapor, and soot. The luminous flame measurements show thin radiating structures corresponding to soot layers and higher …

Multi-Injector Modeling Of Transverse Combustion Instability Experiments, Kevin "James " Shipley

Open Access Theses

Concurrent simulations and experiments are used to study combustion instabilities in a multiple injector element combustion chamber. The experiments employ a linear array of seven coaxial injector elements positioned atop a rectangular chamber. Different levels of instability are driven in the combustor by varying the operating and geometry parameters of the outer driving injector elements located near the chamber end-walls. The objectives of the study are to apply a reduced three-injector model to generate a computational test bed for the evaluation of injector response to transverse instability, to apply a full seven-injector model to investigate the inter-element coupling between injectors …

Design And Development Of Heterogenous Combustion Systems For Lean Burn Applications, Anthony Terracciano

Electronic Theses and Dissertations

Combustion with a high surface area continuous solid immersed within the flame, referred to as combustion in porous media, is an innovative approach to combustion as the solid within the flame acts as an internal regenerator distributing heat from the combustion byproducts to the upstream reactants. By including the solid structure, radiative energy extraction becomes viable, while the solid enables a vast extension of flammability limits compared to conventional flames, while offering dramatically reduced emissions of NOx and CO, and dramatically increased burning velocities. Efforts documented within are used for the development of a streamlined set of design principles, and …

Development Of A Chemical Kinetic Model For The Combustion Of A Synthesis Gas From A Fluidized-Bed Sewage Sludge Gasifier In A Thermal Oxidizer, Luis Martinez

Electronic Theses and Dissertations

The need for sustainability has been on the rise. Municipalities are finding ways of reducing waste, but also finding ways to reduce energy costs. Waste-to-energy is a sustainable method that may reduce bio-solids volume while also producing energy. In this research study bio-solids enters a bubbling bed gasifier and within the gasifier a synthesis gas is produced. This synthesis gas exits through the top of the gasifier and enters a thermal oxidizer for combustion. The thermal oxidizer has an innovative method of oxidizing the synthesis gas. The thermal oxidizer has two air injection sites and the possibility for aqueous ammonia …

Perovskite Catalysts Enhanced Combustion On Porous Media And Thermoelectric Power Conversion, Manuel Robayo

Electronic Theses and Dissertations

A combustion chamber incorporating a high temperature porous matrix was design and tested. The effects and merits of combining combustion on porous media and catalytic enhancement were explored, in addition to the proof of concept of integrating these technologies with simple heat engines, such as thermoelectric generators, to generate efficient and reliable power. The direct observation of the flame during the combustion becomes possible due to a specially designed stainless steel chamber incorporating a quartz window where the initiation and propagation of the combustion reaction/flame was directly visible. The simple design of the combustion chamber allowed for a series of …

An Investigation Of Variable Valve Timing Effects On Hcci Engine Performance, Hrishikesh Abhay Saigaonkar

Dissertations, Master's Theses and Master's Reports - Open

The Homogeneous Charge Compression Ignition (HCCI) engine is a promising combustion concept for reducing NO_x and particulate matter (PM) emissions and providing a high thermal efficiency in internal combustion engines. This concept though has limitations in the areas of combustion control and achieving stable combustion at high loads. For HCCI to be a viable option for on-road vehicles, further understanding of its combustion phenomenon and its control are essential. Thus, this thesis has a focus on both the experimental setup of an HCCI engine at Michigan Technological University (MTU) and also developing a physical numerical simulation model called the …

Effect Of Cetane Number And Volatility On Autoignition And Combustion Of Alternative Fuels And Their Surrogates, Ziliang Zheng

Wayne State University Dissertations

Diesel engine has become a popular choice for trucks, trains, boats, and most other heavy-duty applications. The inherent benefits of diesel engine are high thermal efficiency and specific power output, but there is a concern about high levels of engine-out NOx and particulate matter emissions, which is a major contributor in environment pollution. Moreover, concern about the crisis of crude oil reserves, increasing gas price, trade deficit, and homeland security enhances the interests in alternative fuels.

Unlike conventional diesel fuel, alternative fuels have wide range of properties, such as volatility, cetane number, density, viscosity and lower heating value, which influence …

Simulations And Measurements Of Fuel Film Using Refractive Index Matching Method, Fengkun Wang

Wayne State University Theses

ABSTRACT

SIMULATIONS AND MEASUREMENTS OF FUEL FILM USING REFRACTIVE INDEX MATCHING METHOD

by

FENGKUN WANG

APRIL 2014

Advisor: Dr. Ming-Chia Lai

Major: Mechanical Engineering

Degree: Master of Science

Direct Injection (DI) has been known for its improved performance and efficiency in gasoline spark-ignition engines. However, wall wetting is inevitable and the source of UHC and PM. In order to take advantage of the GDI technology, it is important to investigate spray wall interactions in detail.

Numerical and experimental studies are carried out for spray and wall impingements in an optical constant volume vessel. The fuel film was measured spatially and …

Experimental Investigation Of Syngas Flame Stability Using A Multi-Tube Fuel Injector In A High Pressure Combustor, Sergio Elzar Maldonado

Open Access Theses & Dissertations

Over 92% of the coal consumed by power plants is used to generate electricity in the United States (U.S.). The U.S. has the world's largest recoverable reserves of coal, it is estimated that reserves of coal will last more than 200 years based in current production and demand levels. Integrated Gasification Combined Cycle (IGCC) power plants aim to reduce the amount of pollutants by gasifying coal and producing synThesis gas. SynThesis gas, also known as syngas, is a product of coal gasification and can be used in gas turbines for energy production. Syngas is primarily a mixture of hydrogen and …

Computational Fluid Dynamics Simulation Of United Launch Alliance Delta Iv Hydrogen Plume Mitigation Strategies, Stephen Guimond

Electronic Theses and Dissertations

During the launch sequence of the United Launch Alliance Delta IV launch vehicle, large amounts of pure hydrogen are introduced into the launch table and ignited by Radial-Outward-Firing-Igniters (ROFIs). This ignition results in a significant flame, or plume, that rises upwards out of the launch table due to buoyancy. The presence of the plume causes increased and unwanted heat loads on the surface of the vehicle. A proposed solution is to add a series of fans and structures to the existing launch table configuration that are designed to inject ambient air in the immediate vicinity of the launch vehicle's nozzles …

Tomographic Imaging Of Combustion Zones Using Tunable Diode Laser Absorption Spectroscopy (Tdlas), Avishek Guha

LSU Doctoral Dissertations

This work concentrates on enabling the usage of a specific variant of tunable diode laser absorption spectroscopy (abbr. TDLAS) for tomogaphically reconstructing spatially varying temperature and concentrations of gases with as few reconstruction artifacts as possible. The specific variant of TDLAS used here is known as wavelength modulation with second harmonic detection (abbr. WMS-2f) which uses the wavelength dependent absorbance information of two different spectroscopic transitions to determine temperature and concentration values. Traditionally, WMS-2f has generally been applied to domains where temperature although unknown, was spatially largely invariant while concentration was constant and known to a reasonable approximation (_x0006_+/- 10% …

Numerical Analysis Of Biodiesel Combustion In A Direct Injection Compression Ignition Engine, Kyle D. Morse

Electronic Theses and Dissertations

In this work, simulations of the combustion reaction within an optical Sandia/Cummins N14 direct-injection compression ignition engine are conducted. First, validation of the spray model against liquid and vapor penetration data was conducted using a trial and error method. Secondly, the overall engine model was validated against pressure and temperature data across high and low temperature combustion regimes. The third phase of the work was focused on creating a combustion model for biodiesel. The fourth and final phase was to test the biodiesel combustion model in the pertinent combustion regimes. The agreement with common trends in emissions of biodiesel combustion …