Mechanical Engineering Commons^™

The Extraction Of Shock Waves And Separation And Attachment Lines From Computational Fluid Dynamics Simulations Using Subjective Logic, Matthew C. Lively

Theses and Dissertations

The advancement of computational fluid dynamics to simulate highly complex fluid flow situations have allowed for simulations that require weeks of computation using expensive high performance clusters. These simulations often generate terabytes of data and hinder the design process by greatly increasing the post-processing time. This research discusses a method to extract shock waves and separation and attachment lines as the simulation is calculating and as a post-processing step. Software agents governed by subjective logic were used to make decisions about extracted features in converging and converged data sets. Two different extraction algorithms were incorporated for shock waves and separation …

Multi-Color Cavity Ringdown Based Detection Method And Apparatus, Scott W. Reeve, Susan Davis Allen

Mechanical Engineering - Daytona Beach

A multi-color cavity ringdown based spectrometer system is housed in a light tight enclosure to detect the presence of trace quantities of gas phase molecules emanating from a subject, explosives, drugs, or hazardous materials. A method is also disclosed for simultaneous real time detection of gas phase molecules emanating from explosives, drugs, hazardous materials, a subject's breath skin or bodily fluid.

Efficient Characterization Of Structural Dynamic Responses Under Uncertainties: From Order-Reduced Simulation To Data-Driven Emulation, Zeping Xia

Master's Theses

The efficiency of sampling remains as one of the major challenges for uncertainty analysis in structural dynamics. In the context of numerical experiments, this difficulty primarily lies in the fact that every single run of a numerical model, which usually is of large scale in modern engineering practice, would be expensive in terms of CPU times and memories. Nonetheless, understanding and predicting dynamic characteristics of structural systems with uncertainties is important for structural design, assessment and control. In order to develop fast and economical sampling techniques for characterizing structural dynamics, we explored two categories of methods from two opposite direction: …

Study On The Fracture Toughness Of Friction Stir Welded Api X80, Allan M. Tribe

Theses and Dissertations

High strength low alloy (HSLA) steels have been developed to simultaneously have high yield strength and high fracture toughness. However, in practical applications steel must be welded. Traditional arc welding has proven detrimental to the fracture toughness of HSLA steels. Friction stir welding has recently shown mixed results in welding HSLA steels. The range of welding parameters used in these recent studies however has been very limited. With only a few welding parameters tested, the effect of spindle speed, travel speed, and heat input on the fracture toughness of friction stir welded HSLA steel remains unknown. To understand how the …

The Design And Manufacturing Of The Solar Furnace Reactor Table, Chris Baum, Zach Saylor, Andrew Schiller

Symposium on Research and Creative Expression (SORCE)

The James S. Markiewicz Solar Energy Research Facility at Valparaiso University will concentrate energy from the sun into a reactor containing unprocessed materials. The concentrated light causes a reaction to occur, turning unprocessed materials into alternative energy products. Accurate placement of the reactor at the focal point of the concentrator is necessary to allow the maximum amount of solar energy to enter the reactor. The Reactor Table was designed and built by Valparaiso University students and faculty. The table controls the placement of the reactor at the focal point of the concentrator quickly and easily by using a computer located …

Designing A Calorimeter To Calibrate An Optical Radiative Flux Measurement System To Find The Power Entering A Solar Reactor, Jesse Fosheim, Melissa Meyer, Jonathan Ogland-Hand

Symposium on Research and Creative Expression (SORCE)

A solar furnace has been constructed at Valparaiso University to test the performance of various solar chemical reactors. A primary performance index of a solar chemical reactor is the efficiency, or the fraction of the energy that enters the reactor that is utilized in the chemical reaction. To calculate this efficiency, we must first know how much solar power is entering the reactor. An optical radiative flux measurement system has been developed that gives the solar flux distribution over the aperture of the reactor, but must be calibrated to provide the actual power level. Therefore, a calorimeter was designed and …

Electrical Control And Safety System For Solar Furnace, Parisa Nasserifar, Jason Toberman

Symposium on Research and Creative Expression (SORCE)

The Valparaiso University College of Engineering has recently received a donor gift and a federal earmark to design and manufacture a solar furnace facility. In the solar facility, a heliostat will reflect sunlight straight into the concentrator at every instant. However, due to manufacturing tolerances and inaccuracy in sun’s position model a sun sensor is added in the heliostat sun tracking system. The sun sensor fine adjusts the heliostat’s position so the reflected sunlight is normal to the concentrator. Our goal is to develop a sun sensor that provides an unbalanced output signal when the sensors receive an unbalanced light …

Vu Solar Furnace: Final Design And Construction Of Louver System, Chris Baum, Zach Saylor, Andrew Schiller, Gretchen Vanheeren

Symposium on Research and Creative Expression (SORCE)

Solar energy is an environmentally clean and abundant alternative to the use of fossil fuels. One method of harnessing solar energy, solar thermal electrochemistry, uses a solar furnace to concentrate sunlight and heat a reactor to temperatures around 2000 K. At such high temperatures, metallic oxides can be decomposed into metals and oxygen with minimal electrical work. The solar furnace used for this process consists of a heliostat, which tracks the sun; a concentrator, which focuses the light to a single point; and a reactor in which the chemical reaction takes place. To control the amount of sunlight entering the …

Computational Scheme Guided Design Of A Hybrid Mild Gasifier, You Lu

LSU New Orleans Theses and Dissertations

A mild gasification method has been developed to provide an innovative clean coal technology. The objectives of this study are to (a) incorporate a fixed rate devolatilization model into the existing 2D multiphase reaction model, (b) expand the 2D model to 3D and (c) utilize the improved model to investigate the mild-gasification process and guide modification of the mild-gasifier design. The Eulerain-Eulerian method is employed to calculate both the primary phase (air) and secondary phase (coal particles). The improved 3D simulation model, incorporated with a devolatilization model, has been successfully developed and employed to determine the appropriate draft tube dimensions, …

Technology Portal For Energy Efficient Buildings, Larry D. Hermanson, Daniel Studer, Annie Mroz

STAR Program Research Presentations

Project: Technology Portal for Energy Efficient Buildings

Date: August 2, 2012

Author: Larry Hermanson

Mentor: Daniel Studer

Cohort: Annie Mroz

Lab site: National Renewable Energy Laboratory (NREL)

Buildings account for 71% of the electricity demand and 39% of the primary energy consumption in the United States. The Commercial Buildings Group at NREL provides builders, designers and building owners accurate information to significantly improve the energy efficiency of new and existing buildings. The Technology Portal for Energy Efficient Buildings will increase the accessibility of standardized and credible energy performance data for all building systems, thereby allowing building owners to better evaluate …

Selective Laser Sintering; A Design Of Experiments, Philip David Hopkins, Victor Castillo Phd

STAR Program Research Presentations

Additive Manufacturing (AM), also commonly known as 3D Printing or Rapid Prototyping, is a method of manufacturing that provides for the ability to make intricate internal features and easily customizable parts. The concept is to break a Computer Aided Design (CAD) file into a series of thin layers that are sent to the machine and laid down one layer at a time. Just like any other form of processing, material properties can alter by undergoing this process. Manipulating various parameters of the AM process can allow for different properties to be achieved. For this reason, an in depth study will …

Development Of A Novel Statistical Method And Procedure For Material Characterization And A Probabilistic Approach To Assessing The Hygrothermal Performance Of Building Enclosure Assemblies, Jianhua Zhao

Mechanical and Aerospace Engineering - Dissertations

In this research, a systematic approach was introduced to establish a high quality and comprehensive material database. The method was applied to a great number of materials in different material categories. The database provides a solid base for hygrothermal simulation and further research.

A method was developed to derive the generic material from the material cluster comprising specific materials with similar characteristics. A novel approach was developed by using the generic material to extrapolate less incomplete material data set to full data set that is suitable for the hygrothermal simulation. The approach extends the material database, and hence enhances the …

Magnetic Properties Study Of The Mn-Al System With Additions Of B Or C And Mechanical Milling Techniques, Timothy E. Prost

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Recently a shift in the focus of permanent magnetic research has moved from Rare Earth (RE)-based alloys to those made from more readily available elements. Because of their relatively large magnetocrystalline anisotropy, L1₀ compounds have the potential for use as permanent magnet materials. One particular alloy that is readily available and inexpensive is near equi-atomic manganese and aluminum (Mn₅₀-Al₅₀). First characterized in 1958, it did not receive much attention until more recently when RE supply chain issues made the alloy more attractive for commercial and research applications. The ferromagnetic (FM) τ-phase (L1₀) is …

On Simulation And Modeling Of Turbulent Non-Premixed Reacting Shear Flames At Low And High Pressure, Justin Foster

All Dissertations

A database of simulations of fundamental turbulent H2/O2 and H2/Air shear layer flames has been developed using the direct numerical simulation technique in which all length and time scales of a flow are fully resolved without resort to turbulence modeling. The formulation includes the fully-compressible form of the governing equations, a pressure dependent detailed chemical kinetics scheme (9 species, 19 steps), a cubic real gas equation of state, realistic property models, and generalized heat and mass diffusion models. Simulations were conducted for a temporally developing shear layer geometry and cover a wide range of initial pressures (1 atm < P < 125 atm) and flame Reynolds numbers (850 < Re < 4500). These supercomputing simulations are the largest yet performed for high pressure conditions to the author's knowledge. Computational requirements for the largest simulations included mesh sizes of ~3/4 billion grid points and ~2.2 million CPU-hrs conducted on nearly 4,000 CPU cores on Clemson's Palmetto cluster.

The database …

Static Balancing Of The Cal Poly Wind Turbine Rotor, Derek Simon

Master's Theses

The balancing of a wind turbine rotor is a crucial step affecting the machine’s performance, reliability, and safety, as it directly impacts the dynamic loads on the entire structure.

A rotor can be balanced either statically or dynamically. A method of rotor balancing was developed that achieves both the simplicity of static balancing and the accuracy of dynamic balancing. This method is best suited, but not limited, to hollow composite blades of any size. The method starts by quantifying the mass and center of gravity of each blade. A dynamic calculation is performed to determine the theoretical shaking force on …

Shear-Horizontal Vibration Modes Of An Oblate Elliptical Cylinder And Energy Trapping In Contoured Acoustic Wave Resonators, Huijing He, Jiashi Yang, John A. Kosinski

Department of Mechanical and Materials Engineering: Faculty Publications

We study shear-horizontal free vibrations of an elastic cylinder with an oblate elliptical cross section and a traction-free surface. Exact vibration modes and frequencies are obtained. The results show the existence of thickness-shear and thickness-twist modes. The energy-trapping behavior of these modes is examined. Trapped modes are found wherein the vibration energy is largely confined to the central portion of the cross section and little vibration energy is found at the edges. It is also shown that face-shear modes are not allowed in such a cylinder. The results are useful for the understanding of the energy trapping phenomenon in contoured …

Clean Energy Infrastructure Educational Initiative, Kevin P. Hallinan, James A. Menart, Robert Gilbert

Mechanical and Aerospace Engineering Faculty Publications

The Clean Energy Infrastructure Educational Initiative represents a collaborative effort by the University of Dayton, Wright State University and Sinclair Community College. This effort above all aimed to establish energy related programs at each of the universities while also providing outreach to the local, state-wide, and national communities. At the University of Dayton, the grant has aimed at: solidfying a newly created Master's program in Renewable and Clean Energy; helping to establish and staff a regional sustainability organization for SW Ohio. As well, as the prime grantee, the University of Dayton was responsible for ensuring curricular sharing between WSU and …

Accuracy Of The Home Energy Saver Energy Calculation Methodology, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

The Home Energy Saver (HES) suite offers popular online simulation tools that enable U.S. homeowners and energy professionals to rigorously evaluate home energy use and develop recommendations on how energy can be saved across all end uses. The underlying analytical system is also available as a web service to power third-party energy analysis tools. Given the system's diverse uses, it is important that the simulation is robust and intrinsically accurate. While the engineering methods and assumptions are extensively documented and subjected to peer review, it is useful to evaluate how well HES predicts energy use in occupied homes. In this …

Fabrication And Characterization Of Biocomposites From Polylactic Acid And Bamboo Fibers, Sarah E. Royse

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Environmental concerns have been motivating research in the field of biodegradable materials, especially those from biological sources. Polylactic acid (PLA) is one biopolymer with the potential to replace some standard synthetic polymers. PLA is currently used for fibers, medical sutures, and some packaging, but is still used very little compared with synthetic polymers. One thing that can be done to expand the potential applications of PLA is to add fibers to create composite materials. Bamboo is a good choice for these fibers because it is abundant in many parts of the world, grows very quickly, and is widely unused. Composites …

Champs-Multizone And Virtual Building For Integrated Building Systems Design And Performance Evaluation, Wei Feng

Mechanical and Aerospace Engineering - Dissertations

The ultimate goal of this research was to develop an integrated framework that facilitates performance-based multi-stage design of buildings and comparison between the performance predicted at the design stage and that monitored at operation stage. Such an integrated framework would not only enable design optimization, but also enable confirmation of design intent or diagnosis of performance deficiency, and thus provide feedbacks for future building design. This dissertation study represents the first step toward this ultimate goal, and had the following specific objectives:: 1) developing a combined heat, air, moisture and pollutant transport model for whole building performance simulation; 2) developing …