Mechanical Engineering Commons^™

Parametric And Design Analysis On Thermoelectric Generators, Shouyuan Huang

Open Access Theses

In facing the limited energy source reserves and environmental problems, thermoelectric generators (TEGs) are one of the promising waste heat recovery systems. The modern TEGs for exhaust stream (e.g. from automobiles) can improve the fuel economy by around 5%, taking advantage of the recent developed thermoelectric (TE) materials.

In this work, we aimed at designing a TEG as an add-on module for a gas-phase heat exchanger with maximized power output, and without negative impact (e.g. maintaining a minimum heat dissipation rate from the hot side). We first developed a parametric optimization algorithm using response surface method (RSM) and genetic algorithm …

Investigation Of Digital Pump/Motor Control Strategies, Farid El Breidi

Open Access Dissertations

A pump is the heart of fluid power systems, it has a significant impact on the efficiency of many fluid power systems. Motors are the most common rotary actuators in fluid power systems. State-of-the-art pump/motor units can achieve efficiencies higher than 90% when operating at maximum displacement; however, as the displacement drops, the efficiency of these units drops to below 50%. A new digital pump/motor design aims at increasing these efficiencies by utilizing two electrically controlled high speed on/off valves per displacement chamber; these valves provide the ability to achieve variable displacement and allow freedom in choosing operating strategies. Such …

Modeling Transport Phenomena And Uncertainty Quantification In Solidification Processes, Kyle S. Fezi

Open Access Dissertations

Direct chill (DC) casting is the primary processing route for wrought aluminum alloys. This semicontinuous process consists of primary cooling as the metal is pulled through a water cooled mold followed by secondary cooling with a water jet spray and free falling water. To gain insight into this complex solidification process, a fully transient model of DC casting was developed to predict the transport phenomena of aluminum alloys for various conditions. This model is capable of solving mixture mass, momentum, energy, and species conservation equations during multicomponent solidification. Various DC casting process parameters were examined for their effect on transport …

Experimental, Theoretical And Computational Modeling Of Flow Boiling, Flow Condensation And Evaporating Falling Films, Chirag Rajan Kharangate

Open Access Dissertations

The transition from single-phase to two-phase thermal systems in future space vehicles demands a thorough understanding of phase change methods in reduced gravity, including microgravity. In this study, phase change methods like flow boiling, flow condensation and evaporative falling-films are investigated experimentally, theoretically and computationally.

The experimental part of the study consists of an investigation of the influence of inlet subcooling and two-phase inlet on flow boiling heat transfer and critical heat flux in a horizontal 2.5-mm wide by 5-mm high rectangular channel in different orientations with respect to Earth gravity using FC-72 as working fluid. High-speed video imaging is …

Modeling Of Frame Structures Undergoing Large Deformations And Large Rotations, Hui Liu

Open Access Dissertations

Numerical simulation of large-scale problems in structural dynamics, such as structures subject to extreme loads, can provide useful insights into structural behavior while minimizing the need for expensive experimental testing for the same. These types of problems are highly non-linear and usually involve material damage, large deformations and sometimes even collapse of structures. Conventionally, frame structures have been modeled using beam-frame finite elements in almost all structural analysis software currently being used by researchers and the industry. However, there are certain limitations associated with this modeling approach. This research focuses on two issues, in particular, of modeling frame structures undergoing …

Efficient Modeling Of Sound Source Radiation In Free-Space And Room Environments, Yangfan Liu

Open Access Dissertations

Motivated by the need to develop efficient acoustics simulations for sources in different room environments, a modeling procedure has been proposed that consists of two steps in general: (1) the modeling of the free-space radiation of the source based on measurements in a anechoic environment, and (2) the prediction of the sound field in a room environment based on that free-space information.

To achieve a high modeling efficiency, i.e., to reduce the number of modeling parameters while still maintaining acceptable accuracy, a Multipole Equivalent Source Model (ESM) with undetermined source locations has been developed for the free-space sound field prediction. …

Laser Direct Written Silicon Nanowires For Electronic And Sensing Applications, Woongsik Nam

Open Access Dissertations

Silicon nanowires are promising building blocks for high-performance electronics and chemical/biological sensing devices due to their ultra-small body and high surface-to-volume ratios. However, the lack of the ability to assemble and position nanowires in a highly controlled manner still remains an obstacle to fully exploiting the substantial potential of nanowires. Here we demonstrate a one-step method to synthesize intrinsic and doped silicon nanowires for device applications. Sub-diffraction limited nanowires as thin as 60 nm are synthesized using laser direct writing in combination with chemical vapor deposition, which has the advantages of in-situ doping, catalyst-free growth, and precise control of position, …

Intelligent Control Of A Class Of Nonlinear Systems, Phuong D. Ngo

Open Access Dissertations

The objective of this study is to improve and propose new fuzzy control algorithms for a class of nonlinear systems. In order to achieve the objectives, novel stability theorems as well as modeling techniques are also investigated. Fuzzy controllers in this work are designed based on the fuzzy basis function neural networks and the type-2 Takagi-Sugeno fuzzy models.

For a class of single-input single-output nonlinear systems, a new stability condition is derived to facilitate the design process of proportional-integral Mamdani fuzzy controllers. The stability conditions require a new technique to calculate the dynamic gains of nonlinear systems represented by fuzzy …

Atomistic And Mesoscopic Simulations Of Heat Transfer Across Heterogeneous Material Interfaces, Sridhar Sadasivam

Open Access Dissertations

The study of heat transfer and the associated thermal interface resistance at heterogeneous material interfaces is over 70 years old since the first measurements of thermal interface resistance by Kapitza in 1941. However, recent developments in experimental metrology techniques that enable spectrally-resolved phonon transport measurements at the nanoscale along with the development of high-fidelity simulation methods have provided a renewed interest in the fundamental physics of heat transfer across interfaces. Miniaturized electronic devices and nanostructured materials for energy applications are among technologies that would benefit from a fundamental understanding of interfacial thermal transport. This dissertation focuses on the study of …

Data Driven Low-Bandwidth Intelligent Control Of A Jet Engine Combustor, Nathan L. Toner

Open Access Dissertations

This thesis introduces a low-bandwidth control architecture for navigating the input space of an un-modeled combustor system between desired operating conditions while avoiding regions of instability and blow-out. An experimental procedure is discussed for identifying regions of instability and gathering sufficient data to build a data-driven model of the system's operating modes. Regions of instability and blow-out are identified experimentally and a data-driven operating point classifier is designed. This classifier acts as a map of the operating space of the combustor, indicating regions in which the flame is in a "good" or "bad" operating mode. A data-driven predictor is also …

Implementing And Testing A Panel-Based Method For Modeling Acoustic Scattering From Cfd Input, S. Hales Swift

Open Access Dissertations

Exposure of sailors to high levels of noise in the aircraft carrier deck environment is a problem that has serious human and economic consequences. A variety of approaches to quieting exhausting jets from high-performance aircraft are undergoing development. However, testing of noise abatement solutions at full-scale may be prohibitively costly when many possible nozzle treatments are under consideration. A relatively efficient and accurate means of predicting the noise levels resulting from engine-quieting technologies at personnel locations is needed. This is complicated by the need to model both the direct and the scattered sound field in order to determine the resultant …

Flow Shop Scheduling For Energy Efficient Manufacturing, Hao Zhang

Open Access Dissertations

A large number of new peaking power plants with their associated auxiliary equipment are installed to meet the growing peak demand every year. However, 10% utility capacity is used for only 1%~2% of the hours in a year. Thus, to meet the demand and supply balance through increasing the infrastructure investments only on the supply side is not economical. Alternatively, demand-side management might cut the cost of maintaining this balance via offering consumers incentives to manage their consumption in response to the price signals.

Time-varying electricity rate is a demand-side management scheme. Under the time-varying electricity rate, the electricity price …

Flow Shop Scheduling For Energy Efficient Manufacturing, Hao Zhang

Open Access Dissertations

A large number of new peaking power plants with their associated auxiliary equipment are installed to meet the growing peak demand every year. However, 10% utility capacity is used for only 1%~2% of the hours in a year. Thus, to meet the demand and supply balance through increasing the infrastructure investments only on the supply side is not economical. Alternatively, demand-side management might cut the cost of maintaining this balance via offering consumers incentives to manage their consumption in response to the price signals.

Time-varying electricity rate is a demand-side management scheme. Under the time-varying electricity rate, the electricity price …

Multi-Axial Failure Of High-Performance Fiber During Transverse Impact, Matthew C. Hudspeth

Open Access Dissertations

The effect of projectile nose geometry on ensuing wave development in high-performance yarns is explored during single yarn transverse impact. Special attention has been placed on visualizing the immediate region around the projectile-yarn contact site for 0.30-cal round, 0.30-cal fragment simulation projectiles (FSP), and razor blades using high-speed imaging. Kevlar® KM2, Dyneema®SK76 and AuTx have been impacted at velocities ranging from ∼100 m/s to ∼1200 m/s depending on projectile nose shape, with an emphasis set on determining the critical velocity wherein below said velocity significant development of wave propagation occurs and above said velocity the yarn fails immediately upon impact. …

Preliminary Design Tools In Turbomachinery: Non-Uniformly Spaced Blade Rows, Multistage Interaction, Unsteady Radial Waves, And Propeller Horizontal-Axis Turbine Optimization, Yujun Leng

Open Access Dissertations

Turbomachinery flow fields are inherently unsteady and complex which makes the related CFD analyses computationally intensive. Physically based preliminary design tools are desirable for parametric studies early in the design stage, and to provide deep physical insight and a good starting point for the later CFD analyses. Four analytical/semi-analytical models are developed in this study: 1) a generalized flat plate cascade model for investigating the unsteady aerodynamics of a blade row with non-uniformly spaced blades; 2) a multistage interaction model for investigating rotor-stator interactions; 3) an analytical solution for quantifying the impeller wake convection and pressure wave propagating between a …

Utilizing Tunable Signal Interference Control Topologies With Electromechanical Resonators, Bryce A. Geesey

Open Access Theses

Exploiting knowledge gained from previous investigations of channelized and trans-versal filters, signal interference filters use transmission line differences to generate transmission zeros through phase-shifted combinations of signals at the output of a device. The transmission lines used in these circuits are straightforward to design, but are limited to high-frequency signals (on the order of a few gigahertz) due to the necessity for spatial compactness and low loss. More recent studies have used electromechanical resonators to achieve phase shifting and quality factor improvements at slightly-lower frequencies. These concepts may prove useful if extended to micro- and nanoscale resonators.

To explore signal …

The Effect Of Confinement On The Development Of An Axisymmetric Wall Jet In Confined Jet Impingement, Tianqi Guo

Open Access Theses

Impinging jets have been widely used in the industry for cooling, heating, drying and many other purposes due to their excellent level of mass and heat transfer capacities. When issued into a confinement gap fully filled with working liquid, which is a typical configuration for the compact cooling devices designed to handle the extremely high heat fluxes generated by continuously working electronic components, they are classified as submerged confined impingement jets. Though the complicated flow field induced by the jet has attracted enormous amount of research efforts from heat transfer as well as fluid dynamics points of view, many key …

Mixed Mesh/Nodal Magnetic Equivalent Circuit Modeling Of A Six-Phase Claw-Pole Automotive Alternator, Daniel C. Horvath

Open Access Theses

Magnetic equivalent circuits (MECs) have been employed by many researchers to model the relationship between magnetic flux and current in electromagnetic systems such as electric machines, transformers and inductors [1] ,[2]. Magnetic circuits are analogous to electric circuits where voltage, current, resistance and conductance are the respective counterparts of magneto-motive force (MMF), magnetic flux, reluctance and permeance. The solution of MECs can be accomplished with the plethora of techniques developed for electrical circuit analysis. Specifically, mesh analysis, based on Kirchoff’s Voltage Law (KVL), and nodal analysis, based on Kirchoffs Current Law (KCL), are two very common solution techniques. Once an …

Modifications To Johanson's Roll Compaction Model For Improved Relative Density Predictions, Yu Liu

Open Access Theses

Johanson’s roll compaction model [J.R. Johanson, A rolling theory for granular solids, ASME Journal of Applied Mechanics E32 (1965) 842–848] is modified to improve its predictions of a compacted ribbon’s relative density. Previous work has shown that the maximum roll pressure and ribbon relative density predicted by the Johanson model are not only larger than those predicted from finite element method (FEM) simulations, but also unphysical in some cases. This over-prediction is due to a one-dimensional flow assumption in the Johanson model. Real powder velocity profiles within a roll compactor are non-uniform.

Johanson’s analysis is modified in this work to …

Capacity Optimization Of Battery-Generator Hybrid Power System: Toward Minimizing Maintenance Cost In Expeditionary Basecamp/Operational Energy Applications, Jude C. Onwuanumkpe

Open Access Theses

Low and transient load condition are known to have deleterious impact on the efficiency and health of diesel generators (DGs). Extensive operation under such loads reduces fuel consumption and energy conversion efficiency, and contribute to diesel engine degradation, damage, or catastrophic failure. Non-ideal loads are prevalent in expeditionary base camps that support contingency operations in austere environments or remote locations where grid electricity is either non-existent or inaccessible. The impact of such loads on DGs exacerbates already overburdened basecamp energy logistics requirements. There is a need, therefore, to eliminate or prevent the occurrence of non-ideal loads. Although advances in diesel …

Analysis Of Body Force Effects On Flow Boiling And Condensation With Finite Inlet Quality, Lucas E. O'Neill

Open Access Theses

This study explores flow boiling pressure drop of FC-72 in a rectangular channel subjected to single-side and double-sided heating for vertical upflow, vertical downflow, and horizontal flow with positive inlet quality. Analysis of temporal records of pressure transducer signals is used to assess the influences of orientation, mass velocity, inlet quality, heat flux, and single-sided versus double-sided heating on magnitude of pressure drop oscillations, while fast Fourier transforms of the same records are used to capture dominant frequencies of oscillations. Time-averaged pressure drop results are also presented, with trends focusing on the competing influences of body force and flow inertia, …

Secondary Atomization Of Inelastic Non-Newtonian Liquid Drops In The Bag And Multimode Regimes, Jonathan Rocha

Open Access Theses

Secondary atomization of inelastic shear thinning non-Newtonian liquids in the bag and multimode regimes was studied. Six mixtures were formulated from deionized (DI) water, Avantor Performance Materials' USP grade 100% vegetable based glycerin, and Ashland's Carboxymethylcellulose (CMC-7MF or CMC-7HF). The resulting solutions had power law parameters flow behavior index, n, between 0.71 and 0.93 and consistency index, K, in the range of 0.0464 to 0.37 Pa·s n. The effective viscosity for each mixture was estimated using the power-law model and experimentally measured strain rates up to the initiation time.

Secondary atomization was achieved using a continuous jet setup. Breakup events …

Transportation And Power Solutions For Africa: The Assessment And Optimization Of The Purdue Utility Platform, Jeremy Patrick Robison

Open Access Theses

The Purdue Utility Platform (PUP) is an off-road utility vehicle that was created to improve agricultural productivity in sub-Saharan Africa by providing appropriate transportation and mobile power solutions. The vehicle design has matured to a level where it now requires more robust engineering tools to perform a rigorous assessment of its function. The assessment will be pursued in two areas: durability of the frame and the roll stability of the vehicle. To assess the durability of the frame, a data acquisition system was installed to collect strain gauge information during the vehicle’s operation. This data was then related to an …

Ultra-Thin Boron Nitride Films By Pulsed Laser Deposition: Plasma Diagnostics, Synthesis, And Device Transport, Nicholas Robert Glavin

Open Access Dissertations

This work describes, for the first time, a pulsed laser deposition (PLD) technique for growth of large area, stoichiometric ultra-thin hexagonal and amorphous boron nitride for next generation 2D material electronics. The growth of boron nitride, in this case, is driven by the high kinetic energies and chemical reactivities of the condensing species formed from physical vapor deposition (PVD) processes, which can facilitate growth over large areas and at reduced substrate temperatures. The use of optical emission spectroscopy during plasma growth provides insight into chemistry, kinetic energies, time of flight data, and spatial distributions within a PVD plasma plume ablated …

Characterization Of Pool Boiling Heat Transfer From Porous-Coating-Enhanced Surfaces, Suchismita Sarangi

Open Access Dissertations

Development of techniques for enhancement and optimization of thermal management technologies has been a highly active area of research in recent decades in response to the rapid emergence of compact, high-power electronic systems. Immersion cooling by boiling is one of the preferred methods for high power density applications, due to its passive nature and high heat transfer coefficients obtained. Pool boiling heat transfer has been extensively studied in recent decades to understand the inherent mechanisms yielding the high heat transfer rates, as well as to further enhance the heat transfer by simple modifications or additions to existing approaches. This thesis …

Development Of Distributed Off-Grid Renewable Energy System For Rural African Communities, Mateo Sebastian Guerrero, Menghong Feng

Engagement & Service-Learning Summit

Our Hybrid Energy System team is committed to develop low-cost renewable energy solutions to rural African communities where access to electricity from government grid is not available. According to a World Bank’s report, only 24% of sub-Saharan countries have access to electricity. Our team has been working with local partners to build renewable energy systems since 2008. From 2015 the team has been working on micro hydropower turbine and vertical-axis wind turbine with solar energy system combined. Our current efforts include a prototype design of a wind-solar system, using a new concept of vertical axis wind turbine to harvest wind …

Epics Torch, Madi Rogers, George Townsend, Brandon Henman, Holly Gregory, Patrick Leal, Brennan Mcpherron, Xinyue Pan

Engagement & Service-Learning Summit

The Indiana Bicentennial Commission (IBC) was created by former governor Mitch Daniels to plan and execute a statewide celebration of Indiana’s 200th birthday in 2016. The commission has requested that researchers at Purdue University develop a high-tech Indiana-made flame torch a la the Olympic torch to be used in the celebration and displayed throughout all 92 counties of the state. In addition, the IBC requested that Purdue’s EPICS program develop a kid-friendly torch that can be used alongside the actual torch in relays, celebrations, and community outreach events throughout the state.

By collaborating with Purdue researchers throughout a range of …

4-H Nfpa Fluid Power Challenge, Erika D. Bonnett

Engagement & Service-Learning Summit

The 4-H NFPA Fluid Power Challenge partnered Purdue Polytechnic Institute and Indiana 4-H with the National Fluid Power Association and Center for Compact and Efficient Fluid Power to provide teams of Indiana youth in 6-8th grades with opportunity to learn about hydraulics, engineering design, and other STEM skills. This created an opportunity to give youth a learning experience with STEM through hands-on, experiential learning activities. Youth experienced a one day workshop in which they worked as teams to learn concepts of fluid power through hands-on learning. Teams then went back to their communities and created and designed a fluid power …

A Study On Flow Development In An Apu-Style Inlet And Its Effect On Centrifugal Compressor Performance, Fangyuan Lou

Open Access Dissertations

The objectives of this research were to investigate the flow development inside an APU-style inlet and its effect on centrifugal compressor performance. The motivation arises from the increased applications of gas turbine engines installed with APU-style inlets such as unmanned aerial vehicles, auxiliary power units, and helicopters. The inlet swirl distortion created from these complicated inlet systems has become a major performance and operability concern. To improve the integration between the APU-style inlet and gas turbine engines, better understanding of the flow field in the APU-style inlet and its effect on gas turbine is necessary.

A research facility for the …

Analytical And Experimental Investigation Of Microstructural Alterations In Bearing Steel In Rolling Contact Fatigue, Sina Mobasher Moghaddam

Open Access Dissertations

Rolling Contact Fatigue (RCF) is one the most common failure modes in bearings. RCF is usually associated with particular microstructural alterations. Such alterations (i.e. white etching cracks, butterflies, etc.) which lead to RCF failure are known to be among the most concerning matters to bearing industry.

In the current work, an analytical as well as experimental approaches are used to investigate “butterfly wing” formation, crack initiation and propagation from inclusions. A new damage evolution equation coupled with a FE model is employed to account for the effect of mean stresses and alternating stresses simultaneously to investigate butterfly formation. The proposed …