Heat Transfer, Combustion Commons^™

The Development Of All Solid-State Optical Cryo-Cooler, Junwei Meng

Optical Science and Engineering ETDs

This dissertation describes the development of an all solid-state optical cryo-cooler. Crystals of 10% wt. ytterbium-doped yttrium lithium fluoride (Yb³⁺:YLF) are used to cool an infrared HgCdTe sensor payload to an absolute temperature below 135 K, equivalent to delta T equal 138 K below ambient. This record level of cooling is accomplished with a single stage, in a completely vibration-free environment, with a corresponding cooling power of 190 mW. This milestone is made possible by the design and fabrication of an undoped YLF thermal link that efficiently shields the payload with a non-right angle kink from intense anti-Stokes …

Portable Calorimeter For Fire Experiments, Kayla Collins, Kara Hewson, Christopher Chen, Joel Keddie

Mechanical Engineering

Executive Summary

An oxygen consumption calorimeter works by measuring the heat release rate of a burning substance. This value is calculated by measuring the oxygen and byproducts in smoke from afire.In order to get these values two types of sensors were used. A non-dispersive infrared sensor (NDIR) that measured CO and CO2 and a zirconium O2 sensor were used to find their respective gas concentrations.The design to calculate the heat release rate is focused on maximizing sensor accuracy and portability while simplifying the manufacturing by using off-the-shelf components. The goal included making the system simple to recreate and package in …

Experimental Evaluation Of Heat Leak And Convective Heat Transfer In A Household Freezer., Catherine E. Berghuis

Electronic Theses and Dissertations

Heat leak into household refrigerated cabinets is a key driver affecting energy consumption and efficiency of the cooling system. Additionally, knowledge of heat transfer coefficients of internal surfaces is valuable in the development of cabinet and system level performance simulations. Several studies have examined heat leak of refrigeration units using heat flux sensors (HFS); however, no such studies have used heat flux measurements to derive convective heat transfer coefficients of the refrigerated unit walls. The goal of this study is to evaluate the use of HFS to quantify heat leak into a 490-liter freezer and determine the wall convective heat …

Enhancement Of Phase Change Material Sorbitol By Nanoparticle Inclusion For Improving Thermal Energy Storage Capabilities, Joshua Kasitz

Mechanical Engineering Undergraduate Honors Theses

Thermal management of electronic devices has become an increasingly vital field of study with the rapid miniaturization of many key electrical components. With the significant improvement of semiconductor manufacturing and intensified focus on interconnects, electronic devices have decreased in size at an incredible rate. Decreasing spatial requirements is essential to improving device capabilities as the electronic system is able to incorporate more components. Currently, electronic systems are drastically limited by the capabilities of their cooling mechanisms. Smaller devices lead to large increases in the energy density of the system and require more powerful cooling systems to maintain proper component operating …

Computational Analysis Of A New Planar Mixing Layer Flame Configuration To Study Soot Inception, Carmen Ciardiello

Honors Scholar Theses

The production of soot is omnipresent in society today. Soot is the product of many of the combustion processes that provide the bulk of the usable energy throughout the world. Furthermore, soot particulate poses a great danger to both the environment and all forms of life on Earth. It has proven to pollute ecosystems, foster health problems for human beings, and degrade air quality [1].

These dangers make studying and understanding soot particulate paramount for improving the quality of life. Thus, this study introduces a new flame configuration for studying soot inception. Presently, various common flame configurations have been found …

Emissivity Measurements Of Painted And Aerosol Deposited Thermographic Phosphors (Yag:Dy And Mfg:Mn), Wendy Flores-Brito

Mechanical Engineering ETDs

Combustion is one of the most difficult processes to model. Luminous flames are characteristically sooty, which creates a problem when modeling and calculating the combustion and heat transfer of the process; both of which are highly dependent on temperature and emissivity. Soot particle emissivity as well as gas contributions affect the heat transfer calculation and must be accounted for.

Thermographic phosphors (TP) are ceramic based phosphorescent materials that have a temperature dependent emission that can be exploited to obtain surface and gas temperature measurements, as well as 2D temperature maps. Emissivity knowledge is not needed to obtain temperature and is …

Research Tools And Their Uses For Determining The Thermal Inactivation Kinetics Of Salmonella In Low-Moisture Foods, Soon Kiat Lau

Department of Food Science and Technology: Dissertations, Theses, and Student Research

The reputation of low-moisture foods as safe foods has been crumbling over the past decade due to repeated involvement in foodborne illness outbreaks. Although various pasteurization technologies exist, a majority are thermal processes and have not been well-characterized for pasteurizing low-moisture foods. In addition, the nature of a low-moisture food matrix introduces various experimental complications that are not encountered in high-moisture foods. In this dissertation, the development, building instructions, and characterization of various open source tools for studying the inactivation kinetics of microorganisms in low-moisture foods are described. The first tool is the TDT Sandwich, a dry heating device for …

Thermal Modeling Of Additive Manufacturing Using Graph Theory: Validation With Directed Energy Deposition, Jordan Severson

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

Metal additive manufacturing (AM/3D printing) offers unparalleled advantages over conventional manufacturing, including greater design freedom and a lower lead time. However, the use of AM parts in safety-critical industries, such as aerospace and biomedical, is limited by the tendency of the process to create flaws that can lead to sudden failure during use. The root cause of flaw formation in metal AM parts, such as porosity and deformation, is linked to the temperature inside the part during the process, called the thermal history. The thermal history is a function of the process parameters and part design.

Consequently, the first step …

Quantifying Wicking In Functionlized Surfaces, Maureen Winter, Ryan Regan, Alfred Tsubaki, Craig Zuhlke, Dennis Alexander, George Gogos

UCARE: Research Products

Wicking remains the enigmatic key factor in many research areas. From boiling in power plants, to anti-icing on plane wings, to medical instruments, to heat pipes, efficiency and safety depend on how quickly a surface becomes wet. Yet wicking remains difficult to quantify and define as a property of the surface. This experiment strives to measure the wicking property by examining the rate that a liquid can be pulled out of a container. A superhydrophilic surface is placed in contact with the liquid at the bottom of a tube so that the volume flow rate across the surface can be …

The Application Of Evolutionary Algorithms In Multi-Objective Design And Optimization Of Air Cooled Heatsinks, Younis Osama Abdelsalam, Sajad Alimohammadi, Tim Persoons

Articles

Genetic algorithms (GAs) are considered to be one of the main types of evolutionary algorithms (EAs) and are being increasingly used in various engineering design applications. To a large extent, plate-fin heatsinks are used in the thermal management of compact electronic equipment and data centers. The shape optimization of the heatsinks is not rigorously investigated during the design process of high power electronics. Any improvements in the effectiveness of the heatsinks impact the energy consumed by large-scale information communication technology (ICT) facilities including data centers and telecommunication systems and promote a more sustainable use of raw materials. This paper investigates …

Pool Boiling Inversion On Femtosecond Laser Surface Processed 304 Stainless Steel And Its Impact On Steady-State Time Constants, Justin Costa-Greger, Alfred Tsubaki, Josh Gerdes, Mark Anderson, Craig Zuhlke, Dennis Alexander, Jeff Shield, George Gogos

UCARE: Research Products

FLSP surfaces resulting in boiling inversion require longer times to reach steady-state once inversion has occurred Boiling inversion has been shown to be the result of changing nucleation dynamics in which a large number of nucleation sites activate Increased time required to reach steady-state is linked to the rate at which these nucleation sites activate. Heat fluxes above the boiling inversion point can require up to an additional 3 hours to reach steady-state, compared to the typical 15-20 minutes reported in the literature

Effect Of Chromium Trioxide Coating On The Thermal Performance Of Solar Thermal Collector, Èkram Hadi Alaskaree, Osamah Raad Skheel Alkhafaji, Nizar F. O. Al-Muhsen

Karbala International Journal of Modern Science

This paper compared the thermal performance of two solar collectors. The first collector is coated by a dark black absorbent solar collector, and the second one coated by the chromium trioxide. The results of the second collector show a better selectivity in terms of greater radiation absorption, and less emission compared to the first collector. At the minimum solar irradiance time, the absorbed energy is increased from 908.28J to 1221.5J, and the thermal efficiency is improved from 37.3% to 50.1% when the chromium trioxide coating is used. Besides, at the maximum solar irradiance time, the absorbed energy is increased from …

Dartmouth Formula Racing: Full Electric Battery System Design, Matt Gardner, Jacob Hagler, Ruthie Nordhoff, Otto Salmi

ENGS 89/90 Reports

Dartmouth Formula Racing (DFR) lacked an electrical energy storage system that was Formula Hybrid rules-compliant, optimized for FH events, safe, reliable, and integrated with the rest of their vehicle. Additionally, the team lacked the academic and professional resources required to bring a thorough, analytical approach to the design, testing, and documentation of the new storage system. Our team designed and built a Lithium-Ion battery pack (accumulator) containing energy storage, active cooling, battery management and temperature monitoring systems, and control circuitry compatible with DFR’s vehicle. Collaboration throughout design, fabrication, assembly and testing processes ensured effective knowledge transfer to the DFR team.

Design And Analysis Of A Compact Combustor For Integration With A Jetcat P90 Rxi, Daniel Holobeny

Theses and Dissertations

Ultra Compact Combustors are a novel approach to modern gas turbine combustor designs that look to reduce the overall combustor length and weight. A previous study integrated an Ultra Compact Combustor into a JetCat P90 RXi turbine engine and achieved self-sustained operation with a length savings of 33% relative to the stock combustor. However, that combustor could not operate across the full stock engine performance range due to flameout at increased mass ow rates as reactions were pushed out of the primary zone. To ensure reactions stayed in the primary zone, a new design with a larger combustor volume was …

Effects Of High Freestream Turbulence And Conduction On Film Cooling Effectiveness Of Shaped Holes, Richard A. Macias Jr.

Theses and Dissertations

With technological advancements allowing higher turbine temperatures, film cooling continues to be an important research area. The Film Cooling Rig (FCR) was fitted with a turbulence generator to vary freestream turbulence intensity and length scale, enabling the effects of high freestream turbulence on overall effectiveness to be studied. A cylindrical hole and laidback fan-shaped hole were investigated over a range of Advective Capacity Ratio (ACR) for freestream turbulence intensities of 2%, 10%, and 15%. For a given ACR, increasing the turbulence intensity resulted in lower overall effectiveness values due to the larger heat transfer coefficient that comes from turbulent ow. …

Detonation Confinement In A Radial Rotating Detonation Engine, Kavi Muraleetharan

Theses and Dissertations

Radial Rotating Detonation Engines (RRDE) have provided an opportunity for use of a pressure-gain combustor in a more compact form compared to an axial RDE. A successfully tested RRDE has operated over a wide range of test conditions and produced detonation modes with one, two, and three waves. The presence of multiple waves located the detonation waves to the outer radius, while one wave modes operated closer to the inner radius. Locating the detonation wave closer to the inner diameter resulted in less time for combustion prior to the radial turbine. Subsequently, this tended to decrease efficiency. To attempt to …

Adaptable Clean Energy Laboratory, Joao Marcelo Rocha Belmonte, Marc D. Compere

Sustainability Conference

The Adaptable Clean Energy (ACE) Lab is a real-world, long term, test platform that will guide the courses of the Energy Systems track. The lab will provide realistic electrical and HVAC loads that mimic a solar powered office. The lab is a 20’ high cube shipping container modified with a door, windows, lights computers, air conditioner and appliances. The lab is Net-Zero and powered entirely from the sun. Two insulation test sections expose the exterior walls for research access to real external heat loads in a real building

Residential Thermal Storage And Cooling, Joao Marcelo Rocha Belmonte, Jacob Anderson, Andrew Clarke, Daphne Forester, Bianca Hardtke, Josh Hartman, Marc D. Compere

Sustainability Conference

No abstract provided.

Quaternary Hydrides Pd1-Y-Zagycuzhx Embedded Atom Method Potentials For Hydrogen Energy Applications, Chaonan Zhang

Theses, Dissertations and Capstones

The Pd-H system has attracted extensive attention. Pd can absorb considerable H at room temperature, this ability is reversible, so it is suitable for multiple energy applications. Pd-Ag alloys possess higher H permeability, solubility and narrower miscibility gap with better mechanical properties than pure Pd, but sulfur poisoning remains an issue. Pd-Cu alloys have excellent resistance to sulfur and carbon monoxide poisoning and hydrogen embrittlement, good mechanical properties, and broader temperature working environments over pure Pd, but relatively lower hydrogen permeability and solubility than pure Pd and Pd-Ag alloys. This suggests that alloying Pd with Ag and Cu to create …

Forge Burner, Caleb Desjardins

All Undergraduate Projects

Can small scale blacksmithing operations achieve a level of efficiency in their forge comparable to that of a large scale industry? The causes for the lack of efficiency needed to be pinpointed, and then the geometry of the existing design for the burner could be changed to fix the underlying issues, while still maintaining functionality. The problems with the previous design is the geometry of the intake giving an unknown air/fuel ratio, and the attachment of to the forge allowing the intake air to be contaminated by exhaust gasses. A burner needed to be designed that would solve these problems …

Thermal Performance Of Sierpinski Carpet Fractal Fins At Various Angles Of Inclination In A Natural Convection Environment, Haidar Jamil Khalil

College of Graduate Studies: Theses & Dissertations

As technology advances, higher performance cooling systems are desired to meet numerous thermal management challenges. Extended surfaces, also known as heat sinks or fins, are commonly used to passively dissipate unwanted heat from mechanical and electrical systems. Fractal fins in accordance with the first four iterations (including a base iteration) of the Sierpinski carpet, manufactured from AL-5052, were studied along seven different inclinations from 0° (orientated perpendicular to the direction of gravity) to 90° (orientated parallel to the direction of gravity), in iterations of 15°. The purpose of study was to investigate the thermal performance of the first four fractal …

Generation Of Premix Laminar Flame Speed Library, Sai Prashanth Kumar

Dissertations, Master's Theses and Master's Reports

The Laminar flame speed is an essential parameter in measuring turbulent premixed combustion applied in Spark ignition engines. Instead of using power-law correlations, which is valid only for particular ranges, the procedure for generating a premixed laminar flame speed library is defined using MTU – Master mechanism for a wide range of charge mixture conditions inside an engine combustion chamber: Temperature (300 – 700 K), Pressure (1 – 70 bar) and reactant mixture composition of equivalence ratio (0.4 – 2.0) Laminar flame speed library is generated for methane. The mechanism's performance was improved by adjusting the pre-exponential factor of the …

Energy Conservation And Heat Transfer Enhancement For Mixed Convection On The Vertical Galvanizing Furnace, Dan Mei, Yuzheng Zhu, Xuemei Xu, Futang Xing

Mechanical & Aerospace Engineering Faculty Publications

The alloying temperature is an important parameter that affects the properties of galvanized products. The objective of this study is to explore the mechanism of conjugate mixed convection in the vertical galvanizing furnace and propose a novel energy conservation method to improve the soaking zone temperature based on the flow pattern and heat transfer characteristics. Herein, the present study applied the k-ε two-equation turbulence model to enclose the Navier-Stokes fluid dynamic and energy conservation equations, and the temperature distributions of the steel plate and air-flow field in the furnace were obtained for six Richardson numbers between 1.91 ⋅ 10^{5 …}

Assessment And Improvement Of Computational Fluid Dynamics Methods For Separated Turbulent Flows At Low Reynolds Numbers, Tom Mancuso

Dissertations, Master's Theses and Master's Reports

This study investigates the accuracy of Computational Fluid Dynamics (CFD) models to predict heat transfer in turbulent separated flows at low Reynolds numbers. A novel improvement of a Scale Adaptive technique is also presented. A spectrum of turbulence models is used to simulate flow and heat transfer of two geometries; fully developed flow through a staggered tube bank and a square prism in cross flow. Experimental data for both local heat transfer and velocity data are available in the literature for these cases and have been used extensively evaluate various CFD methods. Six unsteady models were used and the results …

High-Speed Imaging Of Reflected Shockwave-Initiated Combustion, Erik Ninnemann

Electronic Theses and Dissertations, 2020-2023

Shock tubes are considered ideal reactors and are used extensively to provide valuable chemical kinetic measurements, such as ignition delay times and in-situ species time-histories. However, due to nonideal affects the combustion of fuel inside shock tubes can become nonhomogeneous, particularly at low temperatures, which complicates the acquired data. In this work, the combustion of practical fuels used by society are investigated with high-speed imaging. First, high-speed images were captured through the end wall of the shock tube for two hydrogen-oxygen systems. The combustion process was found to initiate in two modes, one that is homogeneous across the fluid medium …

Rotational And Shower Head Cooling Hole Effects On Leading-Edge Jet Impingement Heat Transfer, Weston Olson

Electronic Theses and Dissertations, 2020-2023

Jet Impingement and shower head cooling are critical cooling techniques used to maintain turbine blades at operational temperatures. Jet impingement is extremely effective at removing large amounts of heat flux from the target surface, the inner blade wall, through stagnation point heat transfer. Shower head cooling produces a cooling film around the exterior of the blade, in return reducing external heat flux. The current work consisted of investigating the jet impingement effectiveness with rotational effects for two different cooling schemes. The analysis was conducted numerically using STAR CCM+ with two different turbulence models, the three equation Lag Elliptic Blending K …

A Shock Tube Chemical Kinetic Study Of Ethanol Oxidation At Elevated Pressures, Andrew Laich

Electronic Theses and Dissertations, 2020-2023

Understanding the combustion chemistry of ethanol is critical for continued proliferation and use in future internal combustion engines (ICEs) that will operate in a downsized, turbo-charged, high compression configuration. Detailed chemical kinetic reaction mechanisms already exist for ethanol, which have been validated over a range of operating conditions; however, capturing the conditions that may be seen in future ICEs requires extension of these conditions, namely at elevated pressure. Investigating the kinetics of ethanol existing in a combustion system first involve, for example, understanding a key global metric like ignition delay time (IDT) and measuring major or minor species in a …

Development Of Universal Solver For High Enthalpy Flows Through Ablative Materials, Umran Duzel

Theses and Dissertations--Mechanical and Aerospace Engineering

Atmospheric entry occurs at very high speeds which produces high temperature around the vehicle. Entry vehicles are thus equipped with Thermal Protection Systems which are usually made of ablative materials. This dissertation presents a new solver that models the atmospheric entry environment and the thermal protection systems. In this approach, both the external flow and the porous heat shield are solved using the same computational domain. The new solver uses the Volume Averaged Navier-Stokes Equations adapted for hypersonic non-equilibrium flow, and is thus valid for both domains. The code is verified using analytical problems, set of benchmarks and also a …

Identification Of Heat Release Shapes And Combustion Control Of An Ltc Engine, Radhika Sitaraman

Dissertations, Master's Theses and Master's Reports

Low Temperature Combustion (LTC) regimes have gained attention in internal combustion engines since they deliver low nitrogen oxides (NOx) and soot emissions with higher thermal efficiency and better combustion efficiency, compared to conventional combustion regimes. However, the operating region of these high-efficiency combustion regimes is limited as it is prone to knocking and high in-cylinder pressure rise rate outside the engine safe zone. By allowing multi-regime operation, high-efficiency region of the engine is extended. To control these complex engines, understanding and identification of heat release rate shapes is essential. Experimental data collected from a 2 liter 4 cylinder LTC engine …

Development Of A Process For Thermal And Mechanical Modelling Of Screw-Driven Pellets Extrusion, Kaixiang Shi

Master’s Theses

The overall goal of the thesis project is to develop a process for thermal and mechanical modelling of the screw-driven pellets extrusion process, and applying the model results to design extruder temperature and flow rate controllers.

The proposed extruder is designed for metal 3D printing. The device demonstrates great potential in tackling some of the major issues faced by the metal additive manufacturing community. It eliminates the use of metal powder for workplace and workers safety. It is able to produce end-use parts with industrial grade mechanical and microstructural properties. It utilizes low cost metal-loaded polymer pellets as feedstock. However, …