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Full-Text Articles in Engineering
Computational Valve Plate Design, Paul K. Kalbfleisch
Computational Valve Plate Design, Paul K. Kalbfleisch
Open Access Theses
Axial piston machines are widely used in many industries for their designs compactness, flexibility in power transfer, variable flow rate, and high efficiencies as compared to their manufacturing costs. One important component of all axial piston machines that is a very influential on the performance of the unit is the valve plate. The aim of this research is to develop a design methodology that is general enough to design all types of valve plates and the simple enough not to require advanced technical knowledge from the user. A new style of valve plate designs has been developed that comprehensively considers …
Characterization Of Wake Effects And Loading Status Of Wind Turbine Arrays Under Different Inflow Conditions, Xiangyu Gao
Characterization Of Wake Effects And Loading Status Of Wind Turbine Arrays Under Different Inflow Conditions, Xiangyu Gao
Open Access Theses
The objective of the present work is to improve the accuracy of Actuator Line Modeling (ALM) in predicting the unsteady aerodynamic loadings on turbine blades and turbine wake by assessing different methods used to determine the relative velocity between the rotating blades and wind. ALM is incorporated into a Large Eddy Simulation (LES) solver in OpenFOAM (Open Field Operations and Manipulations). The aerodynamic loadings are validated by experiment results from National Renewable Energy Laboratory (NREL). Turbine wakes are validated by predictions of large eddy simulation using exact 3D blade geometries from a two-blade NREL Phase VI turbine. Three different relative …
Drop Volume Modulation Via Modulated Contact Angle In Inkject Systems, Aaron Fulton
Drop Volume Modulation Via Modulated Contact Angle In Inkject Systems, Aaron Fulton
Open Access Theses
To date, there are limited options in the ability to adjust feature sizes when inkjet printing. The reduction of nozzle size has been the primary method by which smaller features are created. Prior attempts to reduce feature sizes have all come with some restriction or another, as they are only accessible on certain systems, are difficult to manufacture, tune, cause clogging, etc. Few attempts to create droplets of smaller radii than that of the nozzle from which they are produced have been successful. Additionally, many fluids cannot be jetted whatsoever. Existing methods pertain largely to piezoelectric inkjet printing and time …
Bayesian Global Optimization Approach To The Oil Well Placement Problem With Quantified Uncertainties, Zengyi Dou
Bayesian Global Optimization Approach To The Oil Well Placement Problem With Quantified Uncertainties, Zengyi Dou
Open Access Theses
The oil well placement problem is vital part of secondary oil production. Since the calculation of the net present value (NPV) of an investment depends on the solution of expensive partial differential equations that require tremendous computational resources, traditional methods are doomed to fail. The problem becomes exceedingly more difficult when we take into account the uncertainties in the oil price as well as in the ground permeability. In this study, we formulate the oil well placement problem as a global optimization problem that depends on the output of a finite volume solver for the two-phase immiscible flow (water-oil). Then, …
Characterization And Evaluation Of Head Impact Sensors And Varsity Football Helmets, Brian R. Cummiskey
Characterization And Evaluation Of Head Impact Sensors And Varsity Football Helmets, Brian R. Cummiskey
Open Access Theses
An increased understanding of the effects of brain injury in recent years has led to greater attention being given to the topic. A desire to investigate the causal agents of these injuries in athletes has led to the development and use of several devices that track head impacts as well as improving helmet technology to protect players from said impacts. In order to determine which devices are able to best measure head impacts, a Hybrid III headform was used to quantify the accuracy for translational and angular accelerations. Testing was performed by means of administering impacts to a helmet on …
Modeling And Analysis Of A Resonant Nanosystem, Scott L. Calvert
Modeling And Analysis Of A Resonant Nanosystem, Scott L. Calvert
Open Access Theses
The majority of investigations into nanoelectromechanical resonators focus on a single area of the resonator's function. This focus varies from the development of a model for a beam's vibration, to the modeling of electrostatic forces, to a qualitative explanation of experimentally-obtained currents. Despite these efforts, there remains a gap between these works, and the level of sophistication needed to truly design nanoresonant systems for efficient commercial use. Towards this end, a comprehensive system model for both a nanobeam resonator and its related experimental setup is proposed. Furthermore, a simulation arrangement is suggested as a method for facilitating the study of …
Numerical Characterization Of Convective Heat Transfer Of Low-Rise Buildings, Ranchi Chen
Numerical Characterization Of Convective Heat Transfer Of Low-Rise Buildings, Ranchi Chen
Open Access Theses
The convective heat transfer coefficient (CHTC) is an important parameter to evaluate the efficiency of building-integrated photovoltaic/Thermal (PV/T) system and the energy exchange within the turbulent atmospheric boundary layer. Reynolds-average Navier-Stokes approach has been frequently used to predict the CHTC at the surface of low rise roof but incapable of predicting transient behavior of separation, reattachment and recirculation both on the windward and leeward surface. However, Large Eddy Simulation approach (LES) could provide accurate flow field and temperature field around the low rise building. ^ The current study uses Large Eddy Simulation with Smagorinsky-Lily model and the Shear Stress Transport …
Smart V-Belt, Kyle J. Mosier
Smart V-Belt, Kyle J. Mosier
Open Access Theses
The purpose of this research was to develop a method for detecting premature failure in a v-belt using capacitance and resistance readings. Another goal of the research was to detect tension values on the belt using the same readings. Materials of current belts and possible materials for a prototype belt were tested. Materials were chosen, and prototype belts were built. Pulley system configurations were developed and built. Sections of the belt designs were tested for capacitance and resistance before and after various methods of damage. Capacitance was chosen as the better sensing method. Certain layered belt configurations and sheave configurations …
Numerical Simulation And Characterization Of Jet Flows In Indoor Environments, Zhu Shi
Numerical Simulation And Characterization Of Jet Flows In Indoor Environments, Zhu Shi
Open Access Theses
Jet flows are prevalent in indoor environment and other engineering applications. Typical examples in indoor environment include the flow discharged from personal ventilation systems, and the jet exhaled through breathing or coughing. When there is density (or temperature) difference between the jet and surroundings, jet flow becomes stratified jet. Due to its complication, stratified jet flow is difficult to model, especially in the developing or transitional region of the flow. Studying stratified jet flows is of great significance for understanding the mixing dynamics of jet and ambient environment. This is particularly important for optimizing indoor environment design, or obtaining accurate …
Machining As A Mechanical Property Test Revisited, David L. Smith
Machining As A Mechanical Property Test Revisited, David L. Smith
Open Access Theses
There is much need for data on mechanical behavior of metals at high strains and strain rates. This need is dictated by modeling of processes like forming and machining, wherein the material in the deformation zone is subjected to severe deformation conditions atypical of conventional material property tests such as tension and torsion. Accurate flow stress data is an essential input for robust prediction of process outputs. Similar requirements arise from applications in high speed ballistic penetration and design of materials for armor. Since the deformation zone in cutting of metals is characterized by unique and extreme combinations of strain, …
An Experimental Investigation Of A Premixed Laminar Flame Using Tunable Diode Laser And Quantitative Imaging Of Radiation Intensity, Weichao Wang
Open Access Theses
Simultaneous CO concentration and temperature measurements using Tunable Diode Laser Absorption Spectroscopy (TDLAS) are reported in this study. Ro-vibrational transitions of CO, R(27) and R(6) are used for probing absorbance profiles. Premixed ethylene-air flat flame on a McKenna burner is used for creating combustion gaseous products at equivalence ratio 0.83 to 1.82. Nitrogen shroud flow is used for preventing air mixing. Both Direction Absorption (DA) and Wavelength Modulation Spectroscopy (WMS) experiments are conducted. Experimental results are compared with literature and simulation using CHEMKIN and chemical equilibrium. Reasonable agreements are achieved between experiment and simulation. The CO detection limit is determined …
Real-Time Rss-Based Indoor Navigation For Autonomous Uav Flight, Sangjun Lee
Real-Time Rss-Based Indoor Navigation For Autonomous Uav Flight, Sangjun Lee
Open Access Theses
Navigation for the autonomous flight of Unmanned Aerial Vehicles (UAVs) in an indoor space has attracted much attention recently. One of the main goals of an indoor navigation system is developing an alternative method to obtain position information that can replace or complement the global positioning system. While much research has focused on vision-based indoor navigation systems, this paper aims to develop a Received Signal Strength (RSS)-based navigation system, which is a more cost effective alternative. Then, the position and attitude of a UAV can be computed by the fusion of RSS measurements and measurements from the onboard inertial measurement …
Optimizing Electrode Thickness And Material For Laser-Induced Electrothermal Flow, Jian Wei Khor
Optimizing Electrode Thickness And Material For Laser-Induced Electrothermal Flow, Jian Wei Khor
Open Access Theses
In this article, the material dependence of electrothermal flow is studied to optimize an optoelectric particle manipulation technique called Rapid Electrokinetic Patterning (REP). REP utilizes a heat source to produce temperature gradients, which, in this study, are induced by the application of a 1064 nm cw laser. The simultaneous application of an uniform AC electric field assemble colloids on the surface of an electrode that can be moved by translating the laser. The temperature gradients produced from the heat source are crucial in REP as the higher the temperature gradient the faster the electrothermal flow. Thus, optimization of temperature gradients …
Improving Product Design Phase For Engineer To Order (Eto) Product With Knowledge Base Engineering (Kbe), Hanhdung Thi Dinh
Improving Product Design Phase For Engineer To Order (Eto) Product With Knowledge Base Engineering (Kbe), Hanhdung Thi Dinh
Open Access Theses
In industry currently Computer Aided Design (CAD) is an important tool for the modification, analysis, or optimization of the 3D virtual environment that replicates the physical product. CAD software is an efficient and reliable tool. However, as globalization increases customer demands, this process needs to be faster and more efficient to accommodate changing product design situations, especially for Engineer-to- Order (ETO) products. ^ The traditional method of product design process is to operate CAD software without argumentation. Design engineers create CAD prototypes and drawings based on available knowledge and information which comes from engineering experts, company standards, industrial practices as …
Asymptotic Modelling Of A Thermopiezoelastic Anisotropic Smart Plate, Yufei Long
Asymptotic Modelling Of A Thermopiezoelastic Anisotropic Smart Plate, Yufei Long
Open Access Theses
Motivated by the requirement of modelling for space flexible reflectors as well as other applications of plate structures in engineering, a general anisotropic laminated thin plate model and a monoclinic Reissner-Mindlin plate model with thermal deformation, two-way coupled piezoelectric effect and pyroelectric effect is constructed using the variational asymptotic method, without any ad hoc assumptions. Total potential energy contains strain energy, electric potential energy and energy caused by temperature change. Three-dimensional strain field is built based on the concept of warping function and decomposition of the rotation tensor. The feature of small thickness and large in-plane dimension of plate structure …
Delamination Of C/Pekk I-Beam Using Virtual Crack Closure Technique And Cohesive Zone Method, Greeshma Ramakrishna
Delamination Of C/Pekk I-Beam Using Virtual Crack Closure Technique And Cohesive Zone Method, Greeshma Ramakrishna
Open Access Theses
A damage study is conducted on a carbon epoxy/PEKK (poly-ether-ketone-ketone) thermoplastic composite I-Beam, with a pre crack of 100 mm modeled between the top flange and the filler (butt joint between filler and web). This project is in collaboration with Fokker Aerostructures, Netherlands and is part of the Thermoplastic Primary Aircraft Structure innovation program (TAPAS). The C/PEKK I-Beam is modeled after a section of the Gulfstream G650 aircraft's centre beam, which was previously a carbon fiber/epoxy hat-stiffened skin construction. The objective of the thesis is to identify if the crack propagates in the I-Beam within the load range that act …
Design And Heat Transfer Analysis Of Accelerating Distributed Combustion System, Yashovardhan U. Wagh
Design And Heat Transfer Analysis Of Accelerating Distributed Combustion System, Yashovardhan U. Wagh
Open Access Theses
Over the past few decades, there has been a significant increase in greenhouse gases such as CO2, N2O, and CH4 produced from gas turbine engines. Keeping this in mind, current research work is being carried out for reducing NOx produced from combustors. The objective of this research is to determine the feasibility of Distributed Combustion Systems (DCS) for increasing efficiency and reducing NOx emissions. ^ A DCS has a main combustion zone (MCZ) where 90% of the fuel is burned and is followed by a secondary combustion zone (SCZ) in which jets carrying fuel are …