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Direct Simulation And Reduced-Order Modeling Of Premixed Flame Response To Acoustic Modulation, Zheng Qiao
Direct Simulation And Reduced-Order Modeling Of Premixed Flame Response To Acoustic Modulation, Zheng Qiao
Theses and Dissertations
This dissertation introduces a general, predictive and cost-efficient reduced-order modeling (ROM) technique for characterization of flame response under acoustic modulation. The model is built upon the kinematic flame model–G-equation to describe the flame topology and dynamics, and the novelties of the ROM lie in i) a procedure to create the compatible base flow that can reproduce the correct flame geometry and ii) the use of a physically-consistent acoustic modulation field for the characterization of flame response. This ROM addresses the significant limitations of the classical kinematic model, which is only applicable to simple flame configurations and relies on ad-hoc models …
Detailed Chemical Mechanism Generation Of Oxygenated Biofuel, Shrabanti Roy
Detailed Chemical Mechanism Generation Of Oxygenated Biofuel, Shrabanti Roy
Theses and Dissertations
With the increase of global temperature and decrease of fossil fuel sources, biofuels become an excellent alternative in present days. Because of its oxygenated nature, biofuels are found to be more environmentally friendly over fossil fuels. Therefore, in this study, initially two different biofuels: ethanol and 2,5 dimethyl furan (DMF) are considered as an additive to gasoline which shows a significant improvement in its combustion characteristics. Due to this promising result for further studies of these biofuel, details chemical kinetic study of biofuels is considered in this work through generating its mechanism for engine relevant conditions. Detail chemical mechanism PCRL-Mech1 …
Microwave Plasma Assisted Ignition And Combustion Diagnostics, Che Amungwa Fuh
Microwave Plasma Assisted Ignition And Combustion Diagnostics, Che Amungwa Fuh
Theses and Dissertations
Plasmas when coupled to the oxidation process of various fuels have been shown to influence the process positively by improving upon flameholding, reduction in ignition delay time, reduced pollutant emission, etc. Despite all this positive effects being known to the science community, the mechanisms through which the plasmas effects all these enhancements are poorly understood. This is often due to the absence of accurate experimental data to validate theoretical mechanisms and the availability of a myriad sources of plasmas having different chemistries. The goal of this thesis is to further narrow the knowledge gap in the understanding of plasma assisted …
Optical And Laser Spectroscopic Study Of Microwave Plasma-Assisted Combustion, Wei Wu
Optical And Laser Spectroscopic Study Of Microwave Plasma-Assisted Combustion, Wei Wu
Theses and Dissertations
Nonthermal plasma-assisted combustion (PAC) has been demonstrated to be a promising potential method to enhance combustion performance and reduce the pollutant emissions. To better understand the mechanism in PAC, we have conducted a series of studies on the combustion enhancement by plasma using a home-developed PAC platform which employs a nonthermal microwave argon plasma and a suit of optical diagnostic tools including optical imaging, optical emission spectroscopy, and cavity ringdown spectroscopy. A new PAC system in which a continuous atmospheric argon microwave plasma jet is employed to enhance combustion of methane/air mixtures was reported. Reactive species in PAC were characterized …
Injection Timing Effects Of Diesel-Ignited Methane Dual Fuel Combustion In A Single Cylinder Research Engine, Edward Scott Guerry
Injection Timing Effects Of Diesel-Ignited Methane Dual Fuel Combustion In A Single Cylinder Research Engine, Edward Scott Guerry
Theses and Dissertations
Diesel-ignited methane dual fuel combustion experiments were performed in a single cylinder research engine (SCRE). Methane was fumigated into the intake manifold and injection of diesel was used to initiate combustion. The engine was operated at a constant speed of 1500 rev/min, and diesel rail pressure was maintained at 500 bar. Diesel injection timing (SOI) was varied to quantify its impact on engine performance and engine-out ISNOx, ISHC, ISCO, and smoke emissions. The SOI sweeps were performed at different net indicated mean effective pressures (IMEPs) of 4.1, 6.5, 9.5, and 12.1 bar. Intake manifold pressure was maintained at 1.5 bar …
An Experimental Investigation Of Diesel-Ignited Gasoline And Diesel-Ignited Methane Dual Fuel Concepts In A Single Cylinder Research Engine, Umang Dwivedi
Theses and Dissertations
Diesel-ignited gasoline and diesel-ignited methane dual fuel combustion experiments were performed in a single-cylinder research engine (SCRE), outfitted with a common-rail diesel injection system and a stand-alone engine controller. Gasoline was injected in the intake port using a portuel injector, whereas methane was fumigated into the intake manifold. The engine was operated at a constant speed of 1500 rev/min, a constant load of 5.2 bar IMEP, and a constant gasoline/methane energy substitution of 80%. Parameters such as diesel injection timing (SOI), diesel injection pressure, and boost pressure were varied to quantify their impact on engine performance and engineout ISNOx, ISHC, …
Detailed Characterization Of Conventional And Low Temperature Dual Fuel Combustion In Compression Ignition Engines, Andrew C. Polk
Detailed Characterization Of Conventional And Low Temperature Dual Fuel Combustion In Compression Ignition Engines, Andrew C. Polk
Theses and Dissertations
The goal of this study is to assess conventional and low temperature dual fuel combustion in light- and heavy-duty multi-cylinder compression ignition engines in terms of combustion characterization, performance, and emissions. First, a light-duty compression ignition engine is converted to a dual fuel engine and instrumented for in-cylinder pressure measurements. The primary fuels, methane and propane, are each introduced into the system by means of fumigation before the turbocharger, ensuring the airuel composition is well-mixed. Experiments are performed at 2.5, 5, 7.5, and 10 bar BMEP at an engine speed of 1800 RPM. Heat release analyses reveal that the ignition …
Optical And Laser Spectroscopic Diagnostics For Energy Applications, Markandey Mani Tripathi
Optical And Laser Spectroscopic Diagnostics For Energy Applications, Markandey Mani Tripathi
Theses and Dissertations
The continuing need for greater energy security and energy independence has motivated researchers to develop new energy technologies for better energy resource management and efficient energy usage. The focus of this dissertation is the development of optical (spectroscopic) sensing methodologies for various fuels, and energy applications. A fiber-optic NIR sensing methodology was developed for predicting water content in bio-oil. The feasibility of using the designed near infrared (NIR) system for estimating water content in bio-oil was tested by applying multivariate analysis to NIR spectral data. The calibration results demonstrated that the spectral information can successfully predict the bio-oil water content …
A Phenomenological Investigation Of Ignition And Combustion In Alternative-Fueled Engines, Saroj Kumar Jha
A Phenomenological Investigation Of Ignition And Combustion In Alternative-Fueled Engines, Saroj Kumar Jha
Theses and Dissertations
Current diesel technologies involve a broad spectrum of combustion regimes. Previous diesel combustion models either lack the universality across various combustion regimes or suffer computational cost. This dissertation discusses the development of a phenomenological framework to identify and understand key in-cylinder processes that influence the overall performance of a compression ignition engine. The first part of this research is focused on understanding the ignition delay (ID) of diesel fuel in a pilot-ignited partially premixed, low temperature natural gas (NG) combustion engine. Lean premixed low temperature NG combustion is achieved by using small pilot diesel sprays (2-3% of total fuel energy) …
Entropy Generation In A Constant Internal Energy-Volume Combustion Process, Alta Alyce Knizley
Entropy Generation In A Constant Internal Energy-Volume Combustion Process, Alta Alyce Knizley
Theses and Dissertations
This thesis examines the effects of product composition, reactant temperature, reactant pressure, fuel-air equivalence ratio, diluent addition, and fuel composition on entropy generation in a constant internal energy/constant volume combustion process. Equilibrium product composition is shown to produce less combustion-generated entropy than frozen product composition. Using methane as the fuel, it is found that increasing reactant temperature by 100 K decreases entropy generation by 6 to 9 percent, while reactant pressure has little effect on entropy generation. Total entropy generation is increased with excess air and increased diluent addition. For the three fuels considered in this analysis (CH4, C2H5OH, C8H18), …
Enhanced Models For Mixtures Of Fluids In Chemical Equilibrium At High Pressures, Pietro Gaiaschi
Enhanced Models For Mixtures Of Fluids In Chemical Equilibrium At High Pressures, Pietro Gaiaschi
Theses and Dissertations
This thesis is concerned with the numerical simulation of mixtures of chemically reacting fluids at high pressures. Mixture rules are established, accommodating components that do not follow the thermally perfect Equation of State (EoS), and including formulas for the fugacities. Particular attention has been given to the species EoS originally developed by Hirschfelder, Buehler, McGee and Sutton. The Law of Mass Action that governs chemical equilibrium of mixtures of fluids is presented. The common assumption of neglecting fugacities contributions when calculating the equilibrium composition is assessed by comparing complete thermochemical predictions with those obtained by reduced models. For air mixtures …
Uncertainty Analysis Of Net Heat Release Rate Predictions In A Single Cylinder Pilot Compression Ignited Natural Gas Engine, Brandon T. Marvel
Uncertainty Analysis Of Net Heat Release Rate Predictions In A Single Cylinder Pilot Compression Ignited Natural Gas Engine, Brandon T. Marvel
Theses and Dissertations
A zero dimensional single zone model was developed to determine the crank resoled heat release rate at various injection timings (15°-60° BTDC) and the associated uncertainties from a pilot ignited natural gas engine. The uncertainty analysis examines the percentage contribution from various sources of error, including cylinder pressure measurements, intake manifold pressure measurements, and the impact of assumptions such as constant versus temperature dependent specific heat ratios. In particular, uncertainty percentage contributions and uncertainty magnification factors were used to quantify and compare the uncertainties in heat release rates using temperature dependent specific heat ratio correlations to constant specific heat ratio …