Mechanical Engineering Commons^™

Attitude Determination Control Testing System (Helmholtz Cage And Air Bearing), Nicolas Theoret

Honors Theses

The WALI team at Western Michigan University requested a test environment to validate their CubeSat’s de-tumbling control system and hardware. The test environment required a Helmholtz cage and spherical air bearing. The Helmholtz cage provides an adjustable magnetic field to simulate low earth orbit; the spherical air bearing simulates the friction free environment the CubeSat will experience in space. In conjunction, the two components create an adjustable system that simulates a satellite in low earth orbit.

Modeling, Optimizing And Testing Thermoelectric Generators For Liquid-To-Liquid Low Grade Waste Heat Recovery, Ali Eyddan Hamil

Masters Theses

The use of thermoelectric generators (TEGs) for producing electricity from low grade waste heat is thought to be a great solution in the future to reduce the power generation cost because of their advantages of reliability and environmental friendliness. Therefore, the current project aims to study thermoelectric generators for low grade waste heat recovery. In this work, a single unit cell of liquid to liquid thermoelectric generator attached with heat exchangers (heat sinks) is modeled using an internal flow. Its optimum design is obtained based on heat sink optimization and the optimal design method. An analytical model of four unit …

Experimental Characterization And Simulation Of Carbon Nanotube Strain Sensing Films, Nagendra Krishna Chaitanya Tummalapalli

Masters Theses

Carbon Nanotubes (CNTs) have excellent mechanical, electrical and electromechanical properties. These properties led to a lot of novel applications. Due to change in electrical properties under mechanical loading, these composites have potential applications in strain sensors, when these are fabricated as films. CNT-based films are commonly fabricated using different physical and chemical techniques based on the property requirements governing those applications. In this work, CNT films were prepared using wet chemical based methods and chemical vapor deposition techniques.

Plasma chemical vapor deposition using microwave power is used in the first method to deposit films on silicon substrates, using Nickel film …

Development Of An Analytical Model For Beams With Two Dimples In Opposing Directions, Mofareh H. Ghazwani

Masters Theses

Structures such as beams and steel plates can produce potentially high levels of unwanted vibrations and noises in the environment. A method of improving the vibration and acoustic characteristics of beams based on introducing dimples on its surfaces will be presented in this study. This method focuses on creating two dimples in the same and opposite direction on beam’s surface where the effect of dimples on the change in beam’s natural frequencies is the problems of interest.

A boundary value model (BVM) is developed for a beam with two dimples and subjected to various boundary conditions using Hamilton’s Variational Principle. …

Analytical Study Of Miniature Thermoelectric Device, Mohammed Dhannoon

Masters Theses

Miniature thermoelectric devices (TE) have been regarded as hopeful devices to attain efficient cooling in microprocessors and other small-scale devices. To recognize the performances of miniature thermoelectric coolers, a thermoelectric cooling module is theoretically analyzed. Particular attention is paid to the impact of the thermoelectric element length effect and the substrate material type influence on the cooling performance. The electrical contact resistance and thermal contact are taken into account.

Furthermore, miniature thermoelectric is compared with large thermoelectric, and effective material properties of miniature thermoelectric are studied. The obtained results also demonstrate power density (cooling/heating power per unit area of the …

Optimal Design Of Automotive Exhaust Thermoelectric Generator (Aeteg), Hassan Fagehi

Masters Theses

A consumption of energy continues to increase at an exponential rate, especially in terms of automotive spark ignitions vehicles. About 40% of the applied fuel into a vehicle is lost as waste exhaust to the environment. The desire for improved fuel efficiency by recovering the exhaust waste heat in automobiles has become an important subject. The thermoelectric generator (TEG) has the potential to convert exhaust waste heat into electricity as long as it is improving fuel economy. The remarkable amount of research being conducted on TEGs indicates that this technology will have a bright future in terms of power generation. …

Optimization Methodology For Cvt Ratio Scheduling With Consideration Of Both Engine And Cvt Efficiency, Steven Beuerle

Masters Theses

A transmission ratio schedule is developed to optimize the fuel consumption for an automotive continuously variable transmission (CVT) connected to an internal combustion engine (ICE). Although the optimal operating line (OOL) generated from an engine brake specific fuel consumption (BSFC) map can be used to generate a CVT ratio schedule that yields maximum engine efficiency, it was found that OOL-based CVT ratio scheduling does not necessarily offer the best fuel economy because optimal CVT efficiency does not always correspond to OOL tracking. To develop a CVT ratio schedule that can offer the best fuel economy, a novel ratio-scheduling methodology is …

A Genetic Algorithm Incorporating Design Choice For The Preliminary Design Of Unmanned Aerial Vehicles, Kenneth Michael Mull

Masters Theses

Unmanned Aerial Vehicles (UAVs) are currently at the forefront of aerospace technologies. The design of these aircraft is complex and often performance characteristics are coupled to multiple design attributes. At the early design phase both discrete and continuous design choices are present limiting the feasibility of traditional derivative based optimization techniques. In place of these methods, the design space can be explored using a genetic algorithm that mimics the process of natural selection, providing a capable and reliable base airframe constructed from the required performance metrics. By incorporating a genetic multidisciplinary optimization algorithm early in the conceptual design phase, aircraft …

Analytical Modeling And Numerical Simulation Of A Thermoelectric Generator Including Contact Resistances, Shripad Dhoopagunta

Masters Theses

With increasing demand for energy harvesting systems, research has been conducted in different areas in which Thermoelectric Generators (TEG) find their way into the top of many available resources. Out of many energy harvesting systems available, TEGs are comparatively easier to study, to manufacture and also to comprehend while producing enough energy for applications they find use in. They are solid state devices, meaning; they do not have any moving parts and hence makes them durable. Most of the energy that goes out of the automobile as exhaust is reused to power the TEGs. In most of the works that’s …

Design, Modeling And Simulation Of A Thermoelectric Cooling System (Tec), Pooja Iyer Mani

Masters Theses

Thermoelectric Devices are solid state devices which directly convert thermal energy to electrical energy and vice versa. In the recent past, a lot of effort has been made to improve the performance and also the power generated by a thermoelectric device. This is done by attaching heat sinks on either sides of the device. Optimizing heat sinks improves the overall efficiency of it but on the other hand the device also has to be optimized. TECs are mostly used for electronic cooling where the heated electronic devices serve as target that needs to be cooled while air acts as a …

Design And Validation Of An Electro-Hydraulic Pressure-Control Valve And Closed-Loop Controller, Jerry Boza

Dissertations

Electro-hydraulic pressure-control valves are used in many applications, such as manufacturing equipment, agricultural machinery, and aircrafts to name a few. They are often used to actuate hydraulic clutches, such as those found in power shift transmissions. A traditional pressure-control valve with open-loop control algorithm is typically used in clutch applications. This scheme often results in inconsistent or undesirable system behavior due to the nature of open-loop control as well as the nonlinear system dynamics and uncertainties.

In this research two new electro-hydraulic pressure-control valves were designed in order to decouple the valve and control port (hydraulic) dynamics. This was achieved …

Second Law Of Thermodynamics Analysis Of An Internal Combustion Engine Fueled With Methane, Muataz Abotabik

Masters Theses

The second law of thermodynamics is a powerful tool for calculating the amount of energy that can be converted to work (i.e., the exergy or availability of a system), which cannot be predicted using the first law. The objectives of this research project are to quantify the availability during the compression, combustion and expansion processes of a spark-ignited engine fueled with methane; and to highlight differences in the thermo-mechanical availability of the ideal and spark-ignition (SI) engine cycles. A cooperative single-cylinder research engine was used to measure the data required for availability analysis at equivalence ratios ranging between 0.83 and …

An Exploration Of Cubesat Propulsion, Andrew Davis Hine

Masters Theses

The development of new primary propulsion systems for CubeSats with the capability to complete orbital maneuvers has become a principal focus of many within the CubeSat community. One such propulsion device is the 1 cm Busek RF Ion Thruster (BIT-1). For systems such as the BIT-1 to become mission ready and implementable on spacecraft, preliminary testing must be completed to understand how these propulsion devices will perform when placed onboard. The research and testing performed and presented was used to understand how the BIT-1 propulsion device and others like it will interact with small spacecraft. This was accomplished by means …

Least Cost Analysis For Solar Photovoltaic Maintenance Of The Wmu Miller Auditorium Array, Kelsey Pitschel

Honors Theses

The solar photovoltaic array at Miller Auditorium is a 50 kW DC system that has relied on five seasonal angle adjustments and no cleaning measures to reach an average of 64.7 MWh annual energy generation since 2012 1 . This amount of energy generation yields $7,046 in annual energy savings based on current market pricing for end use electricity of $0.1089/kWh 2 . The current adjustment schedule based on seasonal tilts accounts for an annual costs between $760 and $848, but actual adjustments have historically not taken place according to the existing schedule. The analysis focuses on optimizing net energy …

Designing An Accessible Hall Effect Thruster, Matthew Baird

Honors Theses

A group of three Mechanical Engineering students have selected to design a 200 W Hall Effect Thruster to fulfill the Mechanical and Aeronautical Engineering senior design project. Preliminary studies were performed on the theory behind electric propulsion and plasma physics. The group designed the Western Hall Thruster and used COMSOL Multiphysics® simulation software to refine the magnetic circuit. The group then fabricated and performed magnetic testing of their thruster in Western Michigan University’s Aerospace Laboratory for Plasma Experiments. This testing will seek to prove that a standard research HET can be built by universities without substantial financial resources.

Human-Assisted Fluid Power Vehicle, Aaron Huntoon

Honors Theses

The rising cost of energy has prompted industrial and technology companies to research and implement renewable or green energy sources in every aspect of their business. This green technology can consist of sources such as: solar, wind, fluid, or others to create energy from renewable sources. The use of these various sources reduces the pollution associated with standard methods of energy development, and it will ultimately drive costs down to benefit the general population. One of the largest benefactors to the use of renewable energy sources is the transportation industry. Billions of people rely on various modes of transportation every …

The Decomposition Of Hydroxylammonium Nitrate Under Vacuum Conditions, Gregory A. Neff

Masters Theses

This research investigates the decomposition of the ionic liquid: hydroxylammonium nitrate (HAN), under vacuum conditions. All research was conducted at the Aerospace Laboratory for Plasma Experiments (ALPE) at Western Michigan University. Hydroxylammonium nitrate solution 24% wt. in H2O was used consistently throughout this research. A variety of temperatures and pressures ranging from 23°C to 645°C and 6E-3 Torr to 4 Torr, respectively, were used to decompose HAN. The primary gaseous species resulting from these decomposition conditions are N2O, NO, and trace amounts of NO2. The formation of H2O, and N2 is conditional on the experimental conditions, and the formation of …

Mechanical And Aerospace Engineering, 2015-2016, College Of Engineering And Applied Sciences

Mechanical and Aerospace Engineering News

• Letter from the Department Chair
• New Faculty
• Student Success
• University NanoSatellite Program P-Spec Mission
• WALI Student Opportunities
• Study of Blind Cane Vibration