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Full-Text Articles in Engineering
Combustion Dynamics And Heat Transfer In An Ultra Compact Combustor, Brian T. Bohan
Combustion Dynamics And Heat Transfer In An Ultra Compact Combustor, Brian T. Bohan
Theses and Dissertations
The Ultra Compact Combustor (UCC) is an innovative combustion system alternative to a traditional turbine engine burner with the potential to improve engine efficiency with a reduced combustor volume. The UCC shortens the axial length of the combustor, and therefore reduces engine weight, by burning in an annulus and swirling the reactants in the circumferential direction. These length and weight improvements can directly lead to an increased thrust-to-weight rating of the engine. The present research included five objectives which advanced the UCC concept on four fronts; cooling UCC turbine vanes, advanced computational modeling of UCC systems, system air split control …
Thermophotovoltaic Devices: Combustion Chamber Optimization And Modelling To Maximize Fuel Efficiency, Arnold Chris Toppo, Ernesto Marinero, Zhaxylyk Kudyshev
Thermophotovoltaic Devices: Combustion Chamber Optimization And Modelling To Maximize Fuel Efficiency, Arnold Chris Toppo, Ernesto Marinero, Zhaxylyk Kudyshev
The Summer Undergraduate Research Fellowship (SURF) Symposium
Currently, 110 billion cubic meters of natural gas (primarily methane), a potent greenhouse gas, are flared off for environmental and safety reasons. This process results in enough fuel to provide the combined natural gas consumption of Germany and France. The research team developed a thermophotovoltaic device to convert thermal energy to electricity at a high efficiency using proprietary emitters and combustion system. With the current focus being fuel efficiency and the combustion process, the assembly was simulated using ANSYS Fluent modelling software and the following parameters were optimized: air/fuel ratios, flow rates, and inlet sizes. Simultaneously the heat transfer across …
Pore-Resolving Simulation Of Char Particle Gasification Using Micro-Ct, Greg Hingwah Fong, Scott Jorgensen, Simcha L. Singer
Pore-Resolving Simulation Of Char Particle Gasification Using Micro-Ct, Greg Hingwah Fong, Scott Jorgensen, Simcha L. Singer
Mechanical Engineering Faculty Research and Publications
Understanding the interaction between transport, reaction and morphology at the scale of individual char particles is important for optimizing solid fuel gasification and combustion processes. However, most particle-scale models treat porous char particles as an effective porous continuum, even though the presence of large, irregular macropores, voids and fractures render such upscaled treatments mathematically invalid, and the models non-predictive. A new modeling framework is therefore proposed to elucidate the impact of morphology on char particle gasification and combustion. A pore-resolving, transient, three-dimensional simulation for gasification of a realistic coal char particle is developed based on X-ray micro-computed tomography (micro-CT). The …
Kinetic Study Of Free Radical-Radical Reactions Of Combustion Importance At Elevated Pressures, Chao Yan
Kinetic Study Of Free Radical-Radical Reactions Of Combustion Importance At Elevated Pressures, Chao Yan
Dissertations
Combustion mechanisms consist of hundreds elementary reactions of free radicals and stable molecules. Radical-radical elementary reactions play important roles due to the high concentration in which free radicals are accumulated in combustion systems. Radical-radical reactions are typically multi-channel. Some of the channels might be of chain propagation or even chain branching nature, while other channels might be of chain termination nature. The relative importance of different channels is pressure dependent. Compared to radical-molecule reactions, radical-radical reactions are much less studied. This is due to the difficulties of well characterized quantitative production of radical species as well as due to the …
Simulation Of An Ethylene Flame With Turbulence, Soot And Radiation Modeling, Santu Golder
Simulation Of An Ethylene Flame With Turbulence, Soot And Radiation Modeling, Santu Golder
Electronic Theses and Dissertations
This thesis will investigate soot models that are available in commercial codes. We will look at the effect of turbulence models, gravity, soot models and radiation. Simulations will be compared to Coppalle and Joyeux [1]. The flame is an ethylene air diffusion flame at a Reynolds number of 5700. Simulations show the SST turbulence model, one-step soot model and Rosseland radiation model including gravity agree well with experimental data (temperature and soot). Flamelet soot modeling from Carbonell et al. [2] and flamelet radiation modeling from Doom [3] has been incorporated and compared as well.
Design And Experimental Study Of A High Pressure And Supercritical Methane-Oxygen Burner, A S M Arifur Rahim Chowdhury
Design And Experimental Study Of A High Pressure And Supercritical Methane-Oxygen Burner, A S M Arifur Rahim Chowdhury
Open Access Theses & Dissertations
Directly heated supercritical oxy-fuel power cycles have potential to offer a higher thermal efficiency and lower pollutant emissions compared to existing power cycles. Recent thermodynamic analysis of the cycle performed by several groups including the UTEP-Air Liquide research team show that combustion in the vicinity of 300 bar pressure and 1000-1400 K temperature allows for relatively high system efficiencies while operating within the limit of practical combustor materials. However, the realization of directly heated supercritical power cycle requires combustion systems be designed to operate in supercritical conditions and at temperature far below the blowout limit of conventional flames (above 1500 …
NoX Formation In Light-Hydrocarbon, Premixed Flames, Robert T. Hughes
NoX Formation In Light-Hydrocarbon, Premixed Flames, Robert T. Hughes
Theses and Dissertations--Mechanical Engineering
This study explores the reactions and related species of NOx pollutants in methane flames in order to understand their production and consumption during the combustion process. To do this, several analytical simulations were run to explore the behavior of nitrogen species in the pre-flame, post- flame, and reaction layer regions. The results were then analyzed in order to identify all "steady-state" species in the flame as well as the determine all the unnecessary reactions and species that are not required to meet a defined accuracy. The reductions were then applied and proven to be viable.
Investigation Of The Performance And Emissions Characteristics Of Dual Fuel Combustion In A Single Cylinder Idi Diesel Engine, Johnnie L. Williams Jr
Investigation Of The Performance And Emissions Characteristics Of Dual Fuel Combustion In A Single Cylinder Idi Diesel Engine, Johnnie L. Williams Jr
Electronic Theses and Dissertations
Restrictions in the allowable exhaust gas emissions of diesel engines has become a driving factor in the design, development, and implementation of internal combustion (IC) engines. A dual fuel research engine concept was developed and implemented in an indirect injected engine in order to research combustion characteristics and emissions for non-road applications. The experimental engine was operated at a constant speed and load 2400 rpm and 5.5 bar indicated mean effective pressure (IMEP). n-Butanol was port fuel injected at 10%, 20%, 30%, and 40% by mass fraction with neat ultra-low sulfur diesel (ULSD#2). Peak pressure, maximum pressure rise rates, and …