Mechanical Engineering Commons^™

Evaluation Of Turbulence Variable Distributions For Incompressible Fully Rough Pipe Flows, Emilie B. Fowler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The specific turbulent kinetic energy, root-mean-square fluctuating vorticity, and mean-vortexwavelength distributions are presented for fully rough pipe flow. The distributions of these turbulence variables are obtained from a proposed turbulence model. Many of the turbulence models commonly used for computational fluid dynamics are based on an analogy between molecular and turbulent transport. However, traditional k-ε and k-ω models fail to exhibit proper dependence on the molecular viscosity. Based on a rigorous application of the Boussinesq’s hypothesis, Phillips proposed a vorticity-based transport equation for the turbulent kinetic energy. The foundation for this vorticity-based transport equation is presented. In future development of …

Heater Geometry And Heat Flux Effects On Subcooled, Thin Wire, Nucleate Pool Boiling In Microgravity, Troy Munro

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this thesis is to study the effects of microgravity, surface geometry, and heat dissipation per unit area (heat flux) on boiling heat transfer. Boiling is able to move a significant amount of heat for a small area in comparison to other heat transfer methods. Space systems could benefit from the development of thermal management systems that use boiling heat transfer because they would be smaller, more robust, and less expensive. However, boiling is an extremely complicated process which has no comprehensive models to predict its behavior. Multiple correlations have been developed which relate heat transfer efficiencies to …

Bubble Coalescence And Breakup Modeling For Computing Mass Transfer Coefficient, Ryan A. Mawson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Modeling fluid behavior with computer numerical models can be very difficult due to the physical phenomenon which can be present in complex fluid systems. One difficult situation to model is when there is more than one type of fluid in a system. Some of these systems include fluids which do not mix, such as is the case when a liquid and a gas are present. In this situation, the gas phase will form bubbles which are dispersed throughout the liquid phase. Modeling the breakup and coalescence of these bubbles is critical to correctly model this type of situation.

There exist …

Development And Testing Of An Actively Adjustable Stiffness Mechanism, Eleazar Marquez, Robert Freeman, Horacio Vasquez

Mechanical Engineering Faculty Publications

This study presents the comparison of the theoretical and experimental results of the performance of an adjustable stiffness mechanism. In particular, the use of redundant actuation is emphasized in the design of a one degree-of-freedom Watt II mechanism capable of independently controlling the effective stiffness without a change in equilibrium position. This approach is in contrast to spring mechanism designs unable to actively control the spring rate independent of deflection, and with potential applications in various types of suspension and assembly systems. Results indicate that two direct drive brush-type direct current motors are required to drive the redundantly actuated mechanism …

Predictive Simulation Of Gait At Low Gravity Reveals Skipping As The Preferred Locomotion Strategy, Marko Ackermann, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

The investigation of gait strategies at low gravity environments gained momentum recently as manned missions to the Moon and to Mars are reconsidered. Although reports by astronauts of the Apollo missions indicate alternative gait strategies might be favored on the Moon, computational simulations and experimental investigations have been almost exclusively limited to the study of either walking or running, the locomotion modes preferred under Earth's gravity. In order to investigate the gait strategies likely to be favored at low gravity a series of predictive, computational simulations of gait are performed using a physiological model of the musculoskeletal system, without assuming …

The Application Of Origami To The Design Of Lamina Emergent Mechanisms (Lems) With Extensions To Collapsible, Compliant And Flat-Folding Mechanisms, Holly Greenberg

Theses and Dissertations

Lamina emergent mechanisms (LEMs) are a subset of compliant mechanisms which are fabricated from planar materials; use compliance, or flexibility of the material, to transfer energy; and have motion that emerges out of the fabrication plane. LEMs provide potential design advantages by reducing the number of parts, reducing cost, reducing weight, improving recyclability, increasing precision, and eliminating assembly, to name a few. However, there are inherent design and modeling challenges including complexities in large, non-linear deflections, singularities that exist when leaving the planar state, and the coupling of material properties and geometry in predicting mechanism behavior. This thesis examines the …

Numerical Modeling Of High Temperature Bayonet Heat Exchanger And Decomposer For Decomposition Of Sulfur Trioxide, Vijaisri Nagarajan, Yitung Chen, Tzu-Chen Hung, Qiuwang Wang, Valery Ponyavin

College of Engineering: Graduate Celebration Programs

Motivation

• Hydrogen is an attractive energy carrier in the future energy technology.

• Hydrogen is produced from splitting of water through various process namely electrolysis, photo-electrolysis, photo-biological production and thermochemical water-splitting.

• The aim of this study is to numerically investigate fluid flow, heat transfer and chemical reaction in bayonet high temperature heat exchanger and decomposer.

• Parametric studies are performed to achieve maximum decomposition with less pressure drop.

Energy Consumption In Large Wastewater Treatment Plants As A Function Of Wastewater Strength, Timothy Newell, Jacimaria R. Batista, Sajjad Ahmad, Walter Johnson

College of Engineering: Graduate Celebration Programs

Wastewater treatment (WWT) is an energy-intensive process. Strict standards for discharge often require energy intensive advanced treatment technologies. As a result, the number of plants using advanced treatment has increased (Figure 1).

Rising energy costs and concerns about greenhouse gas generation present a major incentive for tracking energy usage of WWT. Energy usage in plant, for instance, typically represents 18 to 30% of the operational budget.

Water efficient fixtures are also increasing loadings of organic matter to plants while lowering or maintaining overall liquid flow. The increased loadings have a significant impact on energy consumption.

Previous work has focused primarily …

A Method For Assessing The Sustainability Of Design In Developing World Projects, Adam Andersen

Master’s Theses

Projects for the developing world usually find themselves at the bottom of an engineer’s priority list. There is often very little engineering effort placed on creating new products for the poorest people in the world. This trend is beginning to change now as people begin to recognize the potential for these projects. Engineers are beginning to try and solve some of the direst issues in the developing world and many are having positive impacts. However, the conditions needed to support these projects can only be maintained in the short term. There is now a need for greater sustainability.

Sustainability has …

Evaluation And Development Of Actuators For Lamina Emergent Mechanisms With Emphasis On Flat Solenoids, Justin Durant Black

Theses and Dissertations

Lamina emergent mechanisms (LEMs) can provide a way to meet the demand for more compact and inexpensive mechanisms. Previous research has developed LEM designs and identified applications for them, but many applications would benefit from suitable actuation techniques. This thesis presents the design considerations and a variety of applicable methods for internal and external LEM actuation in the macro scale. Integrated LEM actuator possibilities have been identified, each with its advantages and disadvantages depending on the application. Shape memory alloys are especially compatible with LEMs. Traditional actuators have also been discussed as a way of actuating a LEM from the …

Latent Heat Thermal Energy Storage With Embedded Heat Pipes For Concentrating Solar Power Applications, Christopher Robak

Master's Theses

An innovative, novel concept of combining heat pipes with latent heat thermal energy storage (LHTES) for concentrating solar power (CSP) applications is explored. The low thermal conductivity of phase change materials (PCMs) used in LHTES presents a design challenge due to slow heat transfer rates during heating and cooling of the material. Heat pipes act to decrease the thermal resistance in the PCM, increasing the overall heat transfer rate sufficiently for use in CSP. First, a laboratory scale experiment is presented to validate the concept of using heat pipes in LHTES to reduce thermal resistance in PCM. A commercial scale …

Application Of Two-Color Pyrometry To Characterize The Two-Dimensional Temperature And Emissivity Of Pulverized-Coal Oxy-Flames, Teri Snow Draper

Theses and Dissertations

Oxy-combustion is a developing technology that enables carbon dioxide (CO2) capture. Flame temperature and emissivity data were taken on a 150 kWth, pulverized-coal, burner flow reactor (BFR) that has been modified to run oxy-combustion with pure CO2 as simulated recycled flue gas. Data were taken at 78 conditions in which three parameters were varied, namely: the swirl angle of the fuel stream, the location of the oxidizer as it exited the burner, and the flow rate of diluent (pure CO2) added to the outer, secondary stream. At each condition, digital color images were obtained using a calibrated RGB camera. The …

Integrating Courses Through Project Based Learning, Lizabeth Schlemer, Sema E. Alptekin, Karen R. Bangs

Industrial and Manufacturing Engineering

Integrating three courses (one sophomore level, two senior level) through Project Based Learning (PBL) within the Industrial Engineering curriculum at the California Polytechnic State University, San Luis Obispo is presented. Three courses (IME 443 Facilities Planning and Design - senior level; IME 420 Simulation - senior level; and IME 223 Process Improvement Fundamentals - sophomore level) were linked by various mechanisms: Common industry projects, common students in two of the three courses; senior students having access to sophomores in their teams to carry out time consuming tasks such as time studies, and sophomores having access to seniors as team members, …

Improving Manufacturing Processes Through Energy Monitoring, Andrew Grzelak

Purdue Polytechnic Masters Theses

Energy efficiency and sustainability are very popular topics in the current field of manufacturing. With the increase in use of automation technology as well as the recent growth in the area of energy management, there is much focus on the overall improvement of manufacturing processes. For this research a project was completed to create a system that could improve both process efficiency as well as decrease energy consumption. By taking a look at the machine level energy consumption of an automated piece of manufacturing equipment, by eliminating waste in process, both energy efficiency and operational efficiency can be improved.

Using …

Cavitation Of A Water Jet In Water, Michael Marshall Wright

Theses and Dissertations

Cavitation is a phenomenon that occurs in liquids when the pressure drops below the vapor pressure of the liquid. Previous research has verified that cavitation bubble collapse is a dynamic and destructive process. An understanding of the behavior of cavitation is necessary to implement this destructive mechanism from an axisymmetric jet for underwater material removal. This work investigates the influence of jet pressure and nozzle diameter on the behavior of a cloud of cavitation bubbles generated by a submerged high-pressure water jet. First, this investigation is put into context with a condensed historical background of cavitation research. Second, a description …

An Investigation Of The Ward Leonard System For Use In A Hybrid Or Electric Passenger Vehicle, Cody L. Telford

Theses and Dissertations

Since the early 1900's demand for fuel efficient vehicles has motivated the development of electric and hybrid electric vehicles. Unfortunately, some components used in these vehicles are expensive and complex. Today's consumer electric vehicles use dangerously high voltage,expensive electronic controllers, complex battery management systems and AC motors. The goal of this research at BYU is to increase safety by lowering the operating voltage and decrease cost by eliminating expensive controllers and decrease the number of battery cells. This paper specifically examines the use of a Ward Leonard Motor Control system for use in a passenger vehicle. The theory of the …

Effects Of Approach Techniques In Place Kicking: A 3d Analysis, Chase M. Pfeifer

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Various studies aim to understand the fundamentals of kicking, primarily the instep kick commonly used by soccer players. Of those studies, most are limited to a 2D analysis using high-speed cameras for position tracking and electromyography to observe muscle activity. The few studies that investigate a 3D model are limited in their position tracking capabilities and focus mainly on joint flexion potentials and foot speed. To the authors knowledge no study of this caliber has been performed on the kinematics and dynamics of place kicking in American football. This thesis uses a 12 camera high-speed motion tracking system to investigate …

Plug-In Hybrid Electric Vehicle Hvac Optimization, Jessica Hartl

Honors Theses

The objective of the proposed project is to convert the current heating ventilating and air conditioning system, or HVAC system, on the plug in hybrid Toyota Prius into a completely electric system. As the vehicle is now, the gas engine is required to provide heat loss for the forced air heating system on extremely cold days. The data, which has been gathered over several years, shows a drop in MPG equivalence from approximately 100-120 MPG on ideal days (70° F) to about 50 MPG equivalence on cooler days. This problem can be solved by increasing the effectiveness of the HVAC …

Optimization Of An Airboat Design, Adam P. Leppek

Honors Theses

Airboats are a common recreational vehicle in southern regions of the United States. A functional prototype of an airboat design was constructed utilizing the manufacturing processes and components available to gain knowledge and experience with the design process. The hull, rudder framework, seating structure, propeller shroud, drive train, and drive unit framework were fabricated at a machine shop. Remaining components were purchased, such as the engine, rudders, and propeller. Welders, mills, lathes, band saws, grinders, hydraulic presses, and power tools were employed in the construction. Drive train and drive unit framework was designed and analyzed using RomaxDesigner, a simulation software …

Hydraulic Test Cell Power Recovery System, Peter M. Kanda

Honors Theses

Wasted power during testing and development of fluid power components is a major concern due to the negative environmental impact and overall associated energy costs. This report describes a developmental hydraulic test stand and several configurations that could result in recovering wasted power. In this test stand, a hydraulic pump capable of 300 horsepower and above is in the design stages within the testing facilities at FEMA Corporation. The pump contained on this test stand will be designed to create a flow that would simulate what a customer directional control valve would see in a real-world application. The standard hydraulic …