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Assessment Of Annular Flow Boiling In The Context Of Computational Fluid Dynamics (Cfd) Simulations, Experiments, And Existing Correlations, Hrishikesh Prasad Ranga Prasad

Dissertations, Master's Theses and Master's Reports

The main objective of the current work is to achieve a better understanding – through modeling and simulation/programming activities – of annular flow-boiling and its applications based on a synthesis of Computational Fluid Dynamics (CFD) simulations, existing correlations, and experiments. A unique and rigorous 2-D CFD simulations technique was developed for annular flow-boiling to propose a correlation for convective component of Heat Transfer Coefficient (HTC) – defined here as flow-boiling in the absence of nucleation. To provide a context for the correlation structure of convective component of HTC, flow-physics details of annular flow-boiling and correlation structure (based on fundamental considerations) …

Influence Of Magnetic Nanoparticles And Magnetic Stress On An Ionic Liquid Electrospray Source, Kurt Joseph Terhune

Dissertations, Master's Theses and Master's Reports

Two electrospray sources were developed to operate on an ionic liquid ferrofluid; one source was a pressure‑fed capillary electrospray source and the other was a novel electrospray source which used a magnetically‑induced instability to produce a peak from which an electric field could extract electrospray. Multiple characteristics of electrospray operation were examined for both sources using faraday plates/cups, a quartz crystal microbalance, a retarding potential analyzer, and a time-of-flight mass spectrometer. The ILFF electrosprays for a capillary source were shown to operate in a mixed ion/droplet regime. The mass flow of the electrospray beam was primarily transported by larger particles …

The Emission And Particulate Matter Oxidation Performance Of A Scr Catalyst On A Diesel Particulate Filter With A Downstream Scr, Sagar Sharma

Dissertations, Master's Theses and Master's Reports

Selective catalytic reduction (SCR) systems along with a NH₃ slip control catalyst (ASC) offers NOₓ conversion efficiency >90 % with NH₃ slip < 20 ppm. However, future heavy duty diesel (HDD) engines are designed for higher engine-out NOₓ to improve fuel consumption. Consequently, there is a strong desire to further improve the NOₓ reduction performance of SCR systems, to meet the 2015 California Optional Low NOₓ Standard. SCR catalysts on a diesel particulate filter provide an effective solution to reduce NOₓ and PM using a single aftertreatment device. It also provides an opportunity to increase the SCR volume to achieve NOₓ conversion efficiency >95 %. A downstream SCR catalyst substrate can be used to get additional NO_x conversion by using the SCRF^® outlet NH₃ to increase the cumulative NOₓ conversion of the system.

In this study, NOₓ reduction, NH₃ slip and PM oxidation performance of a Cu-zeolite SCRF^® with a downstream Cu-zeolite SCR were investigated based on engine experimental data at steady state conditions. The experimental data were collected at varying SCRF^® inlet temperatures, space velocities, inlet …

Simulation Of Diesel Particulate Filter Regeneration Using Lattice Boltzmann Method, Kshitiz Kumar Jain

Dissertations, Master's Theses and Master's Reports

Lattice Boltzmann Method is a novel approach, which has shown promise in solving a wide variety of fluid flow problems including single and multi-phase flows in complex geometries. Volume elements of the fluid domain are considered to be composed of particles and these particles fall under a velocity distribution function at each grid point. Particles collide with each other under the influence of external forces and the rules of collision are defined so as to be compatible with the Navier-Stokes Equation. In the current work, LBM has been applied to Diesel Particulate filters which is a device used for reducing …

Simulation Study On Effect Of Gas Charging And Egr In A Dual-Fuel Engine, Satyavenkata Naga Sai Sharath Gorthy

Dissertations, Master's Theses and Master's Reports

Natural gas combined with diesel as micro pilot has the capabilities of achieving lower NOx and soot emissions. Optimization of the combustion process in engines with natural gas and diesel micro-pilot is essential to achieve higher efficiencies and loads. Gas charging (intake air boosting) and EGR are two technologies which when implemented in the natural gas-diesel engines, provide the opportunity to achieve higher efficiencies and loads and low emissions. Simulation study is one of the approaches to investigate the extent and effects of gas charging and EGR on the performance of the engine. With the rapid improvements over the past …

Impact Of Pretreatment Methods On Fast Pyrolysis Of Biomass, Yash Donepudi

Dissertations, Master's Theses and Master's Reports

Biomass is considered a renewable source of energy with minimum carbon foot print if managed sustainably. The majority of the worlds energy is spend on transportation, and fast pyrolysis of biomass could be a potential route for production of a sustainable liquid transportation fuel. However, there are several hurdles in the conversion process. This work addresses these hurdles by investigating the impact of several pretreatment methods on fast pyrolysis including thermal pretreatment (torrefaction), comminution/grinding, mineral reduction. The impact of important parameters like heat transfer medium, conversion temperature and particle size were also investigated.

A mild thermal pretreatment of biomass (~10-15% …

Performance Of Hard Disk Drives In High Noise Environments, Trinoy Dutta

Dissertations, Master's Theses and Master's Reports

Digital information stored in rotational media, such as Hard Disk Drives (HDD) needs to be reliable and readily accessible. Various studies have been performed on the modal analysis of HDDs and the noise emitted during operation. Analysis performed by Siemens Corporation, IBM and Tyco Fire Protection Products show that HDDs are sensitive to noise. This report initially focusses on identifying the critical frequency ranges and the levels of noise where the performance of the drives reduces. A series of tests have been performed using pink noise at one-third octave frequency bands at sound pressure levels ranging from 80 dB to …

Fea Analysis And Optimization Of Differential Housing For Fatigue Stresses And Fatigue Test Design To Study Skin Effect In Ductile Iron, Swapnil A. Pandey

Dissertations, Master's Theses and Master's Reports

Automotive emission standards are getting more stringent day by day and governments worldwide are moving to reduce emissions from automobiles. In this scenario reducing the weight of automobile components becomes an important design objective to reduce emissions. A 10% reduction of weight in the complete automobile leads to 6-8 percent improvement in mileage (Mhapankar 2015). Also, powertrain components make up for approximately 27% of the total automobile weight and thus optimizing the design of components in the powertrain is an important task (Mhapankar 2015). Statistics show that 26% of component failures in automobiles are part of powertrain and 21% of …

Human Centered Design Of An Open-Drum, Treadle Thresher For Quinoa Farmers In The Andes Of Northern Peru, Robert A. Hayes

Dissertations, Master's Theses and Master's Reports

Growing international demand for quinoa in recent years has led to increased production throughout its South American range, including the Peruvian Andes. Small-scale farmers, who are among the poorest Peruvians, are increasingly growing quinoa for both food security and economic benefit; however, manual harvesting activities, such as threshing, are labor-intensive and time-consuming. This report documents the design, construction and operation of prototype quinoa thresher in a rural village in Northern Peru. In addition, an overview of the history and evolutionary approach to design for the developing world is presented. From this overview, a series of criteria is considered for the …

A 3 D- Fem Study On The Stress Distributions In Pediatric Skull Due To Impact From Free Fall, Suryanshu Walvekar

Dissertations, Master's Theses and Master's Reports

Abstract

Brain is vulnerable to injuries even from low heights of fall. There are many infant casualties who get severe brain injury each year. This research is a simulated study of the stress patterns and values when human infant skull is subjected to free fall. The input velocity was calculated using simple free fall velocity formulas and was fed into the simulation. Model was meshed and refined using Hypermesh software. RADIOSS solver of the Hyperworks package was used to analyze and draw results for the simulation process. Various types of stresses and strains were extracted and plotted against respective drop …

A 3d Fem Comparative Study On The Impact Response Between Human Head And Nocsae Head Due To Free Fall, Amey S. Badhe

Dissertations, Master's Theses and Master's Reports

We all enjoy sports be it watching or playing. Concussion is well known topic when it comes sports related injuries. However, concussion and brain injury is not exclusive to sports and outdoor activities. Sometimes, even the impact due to slip and fall at small heights can cause serious damage to the head and brain. This report studies the response generated in the human head model and the commercially use dummy NOCSAE headform due to drop from height of 2, 3, 4 and 5 feet. Earlier studies have related brain kinetics and head kinematics to concussion and traumatic brain injury (TBI). …

Investigation Of The Use Of 3-D Printer Platform As Building Block For Rapid Design Of Research And Manufacturing Tool, Handy Chandra

Dissertations, Master's Theses and Master's Reports

This thesis attempts to show how an open source 3-D printer platform, the self replicating rapid prototype (RepRap), could be used to accelerate the development of research and manufacturing tools. Two projects are shown as examples, both utilizing components of the 3-D printer platform.

The first project is to develop an instrument capable of performing automated large-area four-point probe measurements. A modified RepRap 3-D Printer with a four-point probe in place of the 3-D printer head is utilized as a precision positioning platform. The printer together with custom designed measurement circuit and software performs automated measurement on multiple points on …

Impact Of E20 Fuel On A High-Performance, Two-Stroke Engine, Jon Gregory Loesche

Dissertations, Master's Theses and Master's Reports

The purpose of this project was to explore the emissions, combustion, and performance effects of running a gasoline/ethanol fuel mixture of 20 percent by volume (E20) in a fuel-injected, two-stroke engine. The engine was operated at five engine speeds that corresponded with the EPA 5-mode emissions test for snowmobile engines. Single parameter sweeps were conducted along with a preliminary recalibration of the test engine at two E0 target values (lambda and mid-pipe temperature) using E20 fuel.

Baseline testing showed that running E20 fuel produced a leaner air/fuel mixture compared to E0, resulting in higher lambda values for all modes and …

Frontal Crash Analysis Of A Conformable Cng Tank Using Finite Element Analysis, Datta Sandesh Manjunath

Dissertations, Master's Theses and Master's Reports

The purpose of this study is to computationally model and analyze a Conformable Compressed Natural Gas (CNG) fuel tank for frontal crashes using Finite Element Analysis. Researchers have developed a CNG fuel tank, which is conformable, non-conventional and non-cylindrical. This tank increases cost efficiency, volumetric efficiency and cargo efficiency in CNG vehicle applications. A lightweight pickup truck (2015 Chevrolet Silverado) has been used to integrate the CNG tanks and field-testing has been conducted to demonstrate the application.

The report mainly focuses on the effective finite element modeling of the chassis, brackets and tanks using HYPERMESH and RADIOSS. The frontal crash …

Minimizing Run Time Of Finite Element Analyses: Applications In Conformable Cng Tank Modeling, Paul M. Roehm

Dissertations, Master's Theses and Master's Reports

REL Inc. has proposed a CNG tank that deviates from typical cylindrical storage methods. The goal of REL working with Michigan Tech is to minimize mass and meet NGV2 safety standards for pressure and drop testing for this tank.

The model has undulated outer surfaces and Schwarz P-surface internal geometry. To accurately mesh this, a small element size is necessary; this creates a model with millions of elements. In explicit analyses, this requires a large amount of computational resources to run.

This report focuses on methods to reduce model run time without reducing accuracy. Methods covered include creating symmetric building …

Advanced Uses For Carbon Nanotubes: A Spherical Sound Source And Hot-Films As Microphones, Micaela M. Thiery

Dissertations, Master's Theses and Master's Reports

Super-aligned carbon nanotube (CNT) thin-film is used to create thermophones. The thermal properties of CNT film allow it to rapidly heat and cool when supplied AC power producing temperature and pressure gradients and, therefore, audible sound. The advantages of CNT thermophones include eliminating all moving components of traditional speakers and reducing the weight of the speaker itself by using CNT film, which is nearly weightless. Additionally, the flexibility of CNT film provides the unique opportunity to construct loudspeakers of various sizes and geometries. In this work, a spherical CNT thermophone is designed, manufactured, and tested for directivity with the overall …

Control Of A Powered Ankle-Foot Prosthesis: From Perception To Impedance Modulation, Guilherme Aramizo Ribeiro

Dissertations, Master's Theses and Master's Reports

Active ankle prostheses controllers are demonstrating gaining smart features to improve the safety and comfort offor users. The perception of user intention to modulate the ankle dynamics is a well-known example of such feature. But not much work focused on the perception of the environment, nor how the environment should be included in the mechanical design and control of the prosthesisprostheses. The proposed work aims to improve the feasibility of integrate the environment perception integration intoto the prostheses controllersler, and to define the desired ankle dynamics, as mechanical impedance, duringof the human walk on different environmental settings. As a preliminary …

Development Of A High-Fidelity Model And Kalman Filter Based State Estimator For Simulation And Control Of Nox Reduction Performance Of A Scr Catalyst On A Dpf, Venkata Rajesh Chundru

Dissertations, Master's Theses and Master's Reports

Reduction of emissions and improving the fuel consumption are two prime research areas in Diesel engine development. The present after-treatment systems being used for emissions control include diesel oxidation catalyst (DOC) for NO, HC and CO oxidation along with catalyzed particulate filters for PM (particulate matter) and selective catalytic reduction (SCR) for controlling NOx emissions. Recently an after-treatment system called SCR catalyst on a DPF capable of simultaneously reducing both NOx and PM emissions has been developed in order to reduce the overall size of the after-treatment system.

The goal of this proposed research is to create a state estimator …

Simulation Of Human Ankle Trajectory During Stance Phase Of Gait, Leslie Castelino

Dissertations, Master's Theses and Master's Reports

A simulation was developed which mimics the human gait characteristics based on the input of an individual’s gait trajectory. This simulation also estimates the impedance of the human ankle based on the ground reaction forces measured by the force plate. This simulation will accept alterations of the following parameters: total body weight, weight of the shank, weight of the foot, trajectories of the shank and foot of the individual and orientation of the force plate, which would generate a new gait trajectory for the ankle during the stance phase of gait. The goal of this simulation was to validate the …

Using Lower Extremity Muscle Activations To Estimate Human Ankle Impedance In The External-Internal Direction, Lauren N. Knop

Dissertations, Master's Theses and Master's Reports

For millions of people, mobility has been afflicted by lower limb amputation. Lower extremity prostheses have been used to improve the mobility of an amputee; however, they often require additional compensation from other joints and do not allow for natural maneuverability. To improve upon the functionality of ankle-foot prostheses, it is necessary to understand the role of different muscle activations in the modulation of mechanical impedance of a healthy human ankle. This report presents the results of using artificial neural networks (ANN) to determine the functional relationship between lower extremity electromyography (EMG) signals and ankle impedance in the transverse plane. …

Multi-Modal And Short-Range Transmission Loss In Ice-Covered, Near-Shore Arctic Waters, Miles B. Penhale

Dissertations, Master's Theses and Master's Reports

In the past century, extensive research has been done regarding the sound propagation in arctic ice sheets. The majority of this research has focused on low frequency propagation over long distances. One of the most commonly used excitation methods for air-ice-water layers has been explosives. However, environmental regulation has become more stringent, disallowing the use of almost all explosive excitation types. Due to changing climate conditions in these environments, new experimentation is warranted to determine sound propagation characteristics in, through, and under thin ice sheets, in shallow water, over short distances. In April, 2016 several experiments were conducted approximately 2 …

Effect Of Spark Advance And Fuel On Knocking Tendency Of Spark Ignited Engine, Abhay S. Joshi

Dissertations, Master's Theses and Master's Reports

Knock, in spark ignition engine is the combustion caused by the autoignition of the fuel-air mixture. It is the phenomenon that limits engine performance and thermal efficiency. Knock also has an adverse effect on emissions and fuel economy. Engine designers target engines with maximum power and torque output without compromising on fuel economy. Engine downsizing is the method generally adopted. The main goal of engine downsizing is to achieve better fuel economy while increasing the power and torque output of the engine. Better fuel economy is achieved by reducing the displaced volume which in turn means a much higher brake …

Surface Ozone And Its Precursors At Summit, Greenland: Comparison Between Observations And Model Simulations, Yaoxian Huang, Shiliang Wu, Louisa J. Kramer, Detlev Helmig, Richard E. Honrath

Michigan Tech Publications

Recent studies have shown significant challenges for atmospheric models to simulate tropospheric ozone (O3/and its precursors in the Arctic. In this study, ground-based data were combined with a global 3-D chemical transport model (GEOS-Chem) to examine the abundance and seasonal variations of O3 and its precursors at Summit, Greenland (72.34° N, 38.29° W; 3212 ma.s.l.). Model simulations for atmospheric nitrogen oxides (NOx/, peroxyacetyl nitrate (PAN), ethane (C2H6/, propane (C3H8/, carbon monoxide (CO), and O3 for the period July 2008-June 2010 were compared with observations. The model performed well in simulating certain species (such as CO and C3H8/, but some significant …