Digital Commons Network^™

Quantification Of Auto-Ignition In Diesel Engines, Umashankar M. Joshi

Wayne State University Dissertations

Efforts have been made previously by researchers to quantify the auto-ignition quality of fuels by calculating global activation energy using Arrhenius plots with data measured for the ignition delay period (ID). Large variation in the activation energy of fuels has been observed even for fuels with closer CN values. More recently, the activation energy values obtained by Kook et al in (2005) on an optical engine do not agree with data obtained in an identical metallic engine by Jayakumar using fuels of same CN.

The disparity in their results can be attributed to the differences in ignition delay (ID) and …

Methodology For Validating Multi-Dimensional Engine Combustion Models And Fuel Surrogates Using An Optically Accessible Compression Ignition Engine, Xin Yu

Wayne State University Dissertations

In response to increasingly stringent engine emissions regulation, three dimensional in-cylinder combustion modeling is increasingly being used as a tool to optimize the combustion process and reduce the cost of experimental testing. Due to the complexity of the physical and chemical interactions involved in the in-cylinder combustion process, the engine combustion model consists of numerous sub-models developed under pre-defined initial and boundary conditions requiring further model calibration depending on different engine applications. Fuel surrogates, one of those sub-models developed for different combustion applications, may not capture all the behavior when applied to the varying temperature-pressure conditions present in a compression …

Specialized Inter-Particle Interaction Lbm For Patterned Superhydrophobic Surfaces, Amal Saeed Yagub

Wayne State University Dissertations

SPECIALIZED INTER-PARTICLE INTERACTION LBM FOR PATTERNED SUPERHYDROPHOBIC SURFACES

by

AMAL S. YAGUB

ABSTRACT:

Superhydrophobic surface characteristics are important in many industrial applications, ranging from the textile to the military. It was observed that surfaces fabricated with nano/micro roughness can manipulate the droplet contact angle, thus providing an opportunity to control the droplet wetting characteristics. The Shan and Chen (SC) lattice Boltzmann model (LBM) is a good numerical tool, which holds strong potentials to qualify for simulating droplets wettability. This is due to its realistic nature of droplet contact angle (CA) prediction on flat smooth surfaces. But SC-LBM was not able …

Edge Fracture Prediction Of Dual Phase Steels With Consideration Of Microstructures, Ming Wen

Wayne State University Dissertations

In recent years, Advanced High Strength Steels (AHSS) have been used for the lightweight structural design and manufacturing in automotive industry. This class of sheet metals are prone to edge fracture during stamping production, and the fracture often occurs at much lower strain than that predicted based on the forming limit curves. The uncertainty in predicting edge fracture represents a great challenge in the application of AHSS. This dissertation is focused on the better understanding of edge fracture phenomenon through experimental observation and computer modeling with the consideration of microstructure effect.

In this dissertation, Hole Expansion (HE) test was used …

Analysis Of A Dual Scissored-Pair,Variable-Speed, Control Moment Gyroscope Driven Spherical Robot, Richard Chase

Wayne State University Dissertations

The objective of this research is to compare barycenter offset based designs of spherical robots to control moment gyroscope (CMG) based designs in order to determine which approach is most effective. The first objective was to develop a list of current state of the art designs in order to gain an overall understanding of what the obstacles in this area of research were. The investigation showed that barycenter offset designs can produce a low, continuous output torque, whereas CMG based designs can usually only produce a high, momentary output torque. The second objective was to develop a CMG based design …

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 …

High-Performance Accelerometer Based On Asymmetric Gapped Cantilevers For Physiological Acoustic Sensing, Yating Hu

Wayne State University Dissertations

Continuous or mobile monitoring of physiological sounds is expected to play important role in the emerging mobile healthcare field. Because of the miniature size, low cost, and easy installation, accelerometer is an excellent choice for continuous physiological acoustic signal monitoring. However, in order to capture the detailed information in the physiological signals for clinical diagnostic purpose, there are more demanding requirements on the sensitivity/noise performance of accelerometers. In this thesis, a unique piezoelectric accelerometer based on the asymmetric gapped cantilever which exhibits significantly improved sensitivity is extensively studied. A meso-scale prototype is developed for capturing the high quality cardio and …

Jp-8 Surrogates For Diesel Engine Application: Development, Validation, And Cfd Simulation, Amit Shrestha

Wayne State University Dissertations

Recently, diesel engine cycle simulation has been acknowledged as an effective way for the development and performance optimization of compression ignition engines operating on a variety of fuels. The goal of this research was, therefore, to develop a JP-8 surrogate with a limited number of fuel components so that its chemical mechanism could be developed for its use with computational fluid dynamics (CFD) codes for enabling time-efficient diesel engine cycle simulation. In order to achieve this goal, a new approach was developed for the formulation of surrogate for compression ignition engine application. The development approach required the surrogate to match …

Non-Linear Robust Observers For Systems With Non-Collocated Sensors And Actuators, Constantine Mastory

Wayne State University Dissertations

Challenges in controlling highly nonlinear systems are not limited to the development of sophisticated control algorithms that are tolerant to significant modeling imprecision and external disturbances. Additional challenges stem from the implementation of the control algorithm such as the availability of the state variables needed for the computation of the control signals, and the adverse effects induced by non-collocated sensors and actuators.

The present work investigates the adverse effects of non-collocated sensors and actuators on the phase characteristics of flexible structures and the ensuing implications on the performance of structural controllers. Two closed-loop systems are considered and their phase angle …

Evaluation Of Nozzle Geometry On High Pressure Gasoline Direct Injection Spray Atomization, Mark Shost

Wayne State University Dissertations

This research presents a critical study of injector nozzle geometry on high-pressure Gasoline Direct Injection, GDi, injector spray morphology. The study was conducted with the aid of multi-fluid Volume-of-Fluid, Large-Eddy-Simulation, VOF-LES, method. Alternative nozzle geometries, that are the subject of current interest including varying nozzle hole length to diameter ratio, counter-bore presence and nozzle-hole skew-angle geometry, are studied in detail in order to provide insight into their specific influence on spray plume targeting and jet primary breakup characteristics. A comparison of the simulation results with near-field shadowgraph and Mie scatter imaging as well as phase-contrast x-ray imaging is provided. When …

Pedestrian Head Protection During Car To Pedestrian Accidents: In The Event Of Primary Impact With Vehicle And Secondary Impact With Ground, Vishal Gupta

Wayne State University Dissertations

Current regulations for assessing pedestrian safety use a simplified test setup that ignores many real-world factors. In particular, the level of protection is assessed using a free-motion headform impacting the vehicle's hood at a fixed angle. As such, this test setup does not capture the effect due to the vehicle front-end profile, nor does it comprehend injury due to a possible secondary impact of the pedestrian's head with ground. This thesis aims to numerically simulate vehicle to pedestrian crashes to develop knowledge that may suggest ways to improve safety above and beyond the regulatory tests. Inputs to the simulations include …

Visualizing Interior And Exterior Jet Aircraft Noise, Manmohan Singh Moondra

Wayne State University Dissertations

In today's competitive aerospace industry, the quest for quiet has drawn significant attention to both the interior and exterior design of an airplane. Understanding the noise generation mechanisms of a jet aircraft is a crucial first step toward developing the most cost-effective noise and vibrations abatement methods. In this investigation, the Helmholtz Equation Least Squares (HELS) based nearfield acoustic holography will be used to understand noise transmission caused by jet engine and turbulence into the fuselage of a jet aircraft cruising at 30,000 ft.

Modern propulsive jet engines produce exterior noise sources with a high amplitude noise field and complicated …

Communication Protocol Design Considerations For Highway Vehicle Platoons And Enhanced Networked Robustness By Stochastic Dithers, Lijian Xu

Wayne State University Dissertations

Highway platooning of vehicles has been identified as a promising framework in

developing intelligent transportation systems. By autonomous or semi-autonomous

vehicle control and inter-vehicle coordination, an appropriately managed platoon can

potentially offer enhanced safety, improved highway utility, increased fuel economy,

and reduced emission. This thesis is focused on quantitative characterization of impact

of communication information structures and contents on platoon safety. By

comparing different information structures which combine front sensors, rear sensors,

and wireless communication channels, and different information contents such

as distances, speeds, and drivers' actions, we reveal a number of intrinsic relationships

between vehicle coordination and communications in …

Study Of Chaotic Ultrasound And Frequency Sweep Excitations In Sonic Ir Nde Technology, Ding Zhang

Wayne State University Dissertations

Sonic Infrared (IR) Imaging Nondestructive Evaluation (NDE) technology has shown inherent advantages, such as fast detection for all direction and all dimension flaws, for both metal and composite materials. The purpose of this dissertation is to study and investigate the physical process of two most important methods, frequency sweep excitation and chaotic excitation, to improve the defect detection ability of Sonic IR technology.

The tool used in our study is known as finite element analysis (FEA). According to test process of Sonic IR technology, some special technologies were developed in FEA simulation, such as creating cracks with flat contact surfaces …

The Mechanics Of Momentum Transfer From Explosive Charges Buried In Water, In Sand, And In Sand With Fines, David M. Fox

Wayne State University Dissertations

Physical tests involving full-scale systems subjected to blast loads are expensive. The development of more accurate computational and analytical methods to better understand and predict the mechanics of mine blast phenomena could be used to reduce the cost of development of mine protected vehicles and protective equipment for personnel involved in demining and similar activities.

Although the science associated with air blast and blast-related ground shock phenomena is very extensive, that of mine blast, involving explosives buried in soil, is less well developed. In this work, theoretical, experimental, and computational methods are synthesized to better understand some of the mechanisms …

Combustion Visualization And Particulate Matter Emission Of A Gdi Engine By Using Gasoline And E85, Po-I Lee

Wayne State University Dissertations

In order to increase engine efficiency as well as to reduce emission, optimizing combustion is always the challenge in research and product development. Gasoline direct injection (GDI) engines have been popularized due to its higher power density, fuel efficiency, and the possibility for advanced engine technologies over conventional port-fuel-injection (PFI) gasoline engines. However, many issues are heavily investigated, such as air-fuel mixing preparation, fuel wall-wetting, higher HC and PM emissions, catalytic convertor efficiency, knocking, and pre-ignition. Besides, advanced technologies represent higher production cost.

Because of the limited resource of petroleum-based fuels, ethanol is deemed as the alternative fuel for gasoline …

Effect Of Intake Temperature And Boost Pressure On The Auto-Ignition Of Fuels With Different Cetane Numbers And Volatilities, Chandrasekharan Jayakumar

Wayne State University Dissertations

The aim of this research is to investigate the effect of air inlet temperature and boost pressure on the auto-ignition of fuels that have different CNs and volatilities in a single cylinder diesel engine. The inlet air temperature is varied over a range of 30°C to 110°C at a constant intake pressure of 1.1 bar. The boost pressure is varied from 1.1 bar to 1.5 bar at a constant intake temperature of 60°C. All engine tests are run at steady-state conditions. The fuels used are ultra-low-sulfur-diesel (ULSD), JP-8 (two blends with CN 50 & 31) and F-T SPK. Detailed analysis …

Exergetic Analysis Of Hydrogen Combustion Involving Electronically Excited Species, Devon Alan Washington

Wayne State University Dissertations

Plasma-assisted combustion (PAC) is a growing field of research that involves using nonthermal plasma (NTP) to enhance combustion. PAC research involves modeling reaction mechanisms and chemical kinetics. Exergy analysis of combustion devices focuses on combustion irreversibility, including mixing, internal heat transfer, and oxidation. This novel research project merges these two branches of research.

The focus of this work is the application of exergy analysis to PAC systems, to analyze the effect introducing NTP has on trends in exergy destruction associated with oxidation during hydrogen combustion. This was accomplished by developing a plug flow reactor model using the chemical simulation tool …

Ionization In Diesel Combustion For On-Board Diagnostics And Engine Control, Tamer Hassan Badawy

Wayne State University Dissertations

Diesel engines have been known for their high thermal efficiency and specific power output, but there is concern about engine-out NOx and particulate matter emissions. To meet the current emission standards, advanced diesel engines are fitted with electronically controlled fuel injection systems and sophisticated and expensive after-treatment devices. Further improvements are still needed to meet future goals in better fuel economy and the more stringent emission standards. In order to meet these goals, there is a need for the control of the combustion process to reduce engine-out emissions in real-time and reduce the demand on the after-treatment devices. This requires …

Experimental Investigation And Development Of An Extended Two Color Method (Etcm) With Application To Internal Combustion Engines, Elena Florea

Wayne State University Dissertations

The internal combustion engine is on a continuous path of improvement to reduce exhaust gaseous emissions and improve fuel economy. While recent trends in diesel engine development have lowered the EGR requirements, future regulatory pressure will likely result in a reversed trend in the future.

Given this, it is of interest to improve the application range of diagnostic tools such as the two color method (TCM) typically used in evaluating the properties of engine soot, such as temperature and volume fraction. This optical diagnostic method relies on the use of the light emitted by the soot particles along with a …

Structure Borne Noise Analysis Using Helmholtz Equation Least Squares Based Forced Vibro Acoustic Components, Logesh Kumar Natarajan

Wayne State University Dissertations

This dissertation presents a structure-borne noise analysis technology that is focused on providing a cost-effective noise reduction strategy. Structure-borne sound is generated or transmitted through structural vibration; however, only a small portion of the vibration can effectively produce sound and radiate it to the far-field. Therefore, cost-effective noise reduction is reliant on identifying and suppressing the critical vibration components that are directly responsible for an undesired sound. However, current technologies cannot successfully identify these critical vibration components from the point of view of direct contribution to sound radiation and hence cannot guarantee the best cost-effective noise reduction.

The technology developed …

Induced Damping And Its Relationship To Beneficial Energy Harvesting In Dielectric Elastomers With Application To Walking, Heather L. Lai

Wayne State University Dissertations

This dissertation presents a novel, interdisciplinary research which addresses the potential of applying soft polymeric materials to strategically harvest biomechanical energy in a beneficial manner for use as a viable, low power source for on-board electronics. Of particular interest are electroactive polymers (EAP), which unlike other types of electromechanical smart materials such as piezoelectric ceramics, which are often brittle, have low elastic modulus and can exhibit large strains without substantial stress generations. One type of EAP, the dielectric elastomer (DE), which utilizes electrostatic forces built up across the dielectric polymer to convert between electrical and mechanical energy, is employed in …

Simulations And Experiments Of Fuel Injection, Mixing And Combustion In Di Gasoline Engines, Yi Zheng

Wayne State University Dissertations

Direct Injection (DI) has been known for its improved performance and efficiency in gasoline spark-ignition engines. In order to take all the advantages of the GDI technology, it is important to investigate in detail the interactions of fuel spray and combustion system, such as air-fuel mixing, in-cylinder flow development, surface wetting, and turbulence intensity. The characterizations of the internal nozzle flow of DI injector are first studied using the multidimensional computational fluid dynamic (CFD) simulation. In the meanwhile the numerical and experimental studies are carried out to observe the external spray and wall impingements in an optical constant volume vessel. …

Impact Damage Analysis Of Balsa Wood Sandwich Composite Materials, Suof Abdalslam

Wayne State University Dissertations

No abstract provided.

An Integrated Framework For Configurable Product Assortment Planning, Seyed Ali Taghavi Behbahani

Wayne State University Dissertations

A manufacturer's assortment is the set of products or product configurations that the company builds and offers to its customers. While the literature on assortment planning is growing in recent years, it is primarily aimed at non-durable retail and grocery products. In this study, we develop an integrated framework for strategic assortment planning of configurable products, with a focus on the highly complex automotive industry. The facts that automobiles are highly configurable (with the number of buildable configurations running into thousands, tens of thousands, and even millions) with relatively low sales volumes and the stock-out rates at individual dealerships (even …

Spray Characterization Of Flex-Fuel Gasoline Di Injectors And Spray Interaction With Charge Motion In A Variable Valve Actuation Engine, Atsushi Matsumoto

Wayne State University Dissertations

The objective of this study is to understand the characteristics of GDI sprays and behavior of in-cylinder charge motion in a GDI engine which is equipped with variable valve actuation. High speed spray visualization in a spray chamber was conducted for a study of spray development. By Schlieren visualization technique, the effect of different conditions including ambient conditions (temperature, pressure) and injection conditions (fuel type, fuel temperature, nozzle design) on spray formation was discussed in both qualitative and quantitative methods. High-speed visualization of the in-cylinder charge motion was carried out as well using an optical accessible engine. The testing was …

Linear And Non-Linear Deformations Of A Wind Turbine Blade Considering Warping And All Aeroelastic Load Couplings, Fouad Mohammad Mohammad

Wayne State University Dissertations

The structural dynamics behavior of the blade of a horizontal axis wind turbine that reacts to the different components of the aerodynamic loading were studied by many researchers using different approaches and assumptions. In the present research, the author considered all the extensional, torsional and flexural loadings acting on the blade with their couplings, variable airfoil cross sections with warping effects, shear deflection, rotary inertia and with or without blade's pretwist for both the linear small deformation case and the nonlinear large deformation case. To the best knowledge of the author the simultaneous inclusion of all these factors has not …

Multi-Fuel Operation Of Modern Engines; On Board Fuel Identification, Florin Mocanu

Wayne State University Dissertations

Modern engines require enhancement of electronic controls to achieve better fuel economy, higher power density and satisfactory emissions levels while operating safely.

Military vehicles should be capable to run safely and efficiently on any fuel available in the field, therefore on-board fuel identification and adaptation of engine controls to the type of fuel becomes extremely important. In these conditions, the use of an inexpensive, nonintrusive sensor is highly desirable.

The development of a technique based on the measurement of the instantaneous crankshaft speed and engine dynamics could be a convenient solution.

Several such methods have been elaborated at the Center …

Optical Investigation Of Ethanol And N-Heptane Dual-Fuel Partially Premixed Combution In S Reciprocating Engine, Radu Catalin Florea

Wayne State University Dissertations

The details of the dual-fuel combustion of n-heptane and ethanol were investigated in an optically accessible engine representative of light-duty applications. Experimental work involved the application of optical diagnostics such as high-speed imaging of combustion chemiluminescence and soot radiation, spectral measurements and laser induced fluorescence. At the same time, the experimental conditions have been replicated using numerical simulation of chemically reactive in-cylinder flow.

The numerical simulation results, which showed good agreement with the experimental data across several validation approaches, provided an improved understanding of the mechanism responsible for the control of the rate of combustion for dual-fuel operation. The comparison …

Gapped Cantilever For The Enhancement Of Strain Sensitivity And Energy Efficiency, Qinglong Zheng

Wayne State University Dissertations

Cantilever structures have been widely used in a large variety of transducer applications. For cantilever based transducers, piezoresistive/piezoelectric mechanisms has always been a popular choice due to the advantages of being low cost, simple structure and portability. However, low sensitivity is recognized as a major disadvantage of these transducers compared with optical based measurement. In this research, a gapped cantilever structure is proposed to potentially increase the sensitivity by orders of magnitude. In order to guide the design, an advanced analytical model is developed, and the increased strain sensitivity is theoretically demonstrated. In addition, optimizations with this model interestingly reveal …