Heat Transfer, Combustion Commons^™

High Injection Pressure Impinging Diesel Spray Characteristics And Subsequent Soot Formation In Reacting Conditions, Zhihao Zhao

Dissertations, Master's Theses and Master's Reports

The spray impingement in diesel engines attracts the attention of engine researchers in recent decades as the physical size of the engine is reduced. Due to the spray impingement, the atomization, vaporizing and air-fuel mixing quality is altered compared to a free spray. For emission control, soot is one of the major particulate emissions from diesel combustion and its formation in an impinged spray is worthy to be investigated.

Firstly, to understand the impinged spray characteristics, the experiments for both non-vaporizing and reacting conditions were conducted in a constant volume combustion vessel. The impinged spray was captured by a high-speed …

Integrated Torrefaction-Extrusion System For Conversion Of Fiber-Plastic Wastes Into Solid Fuels, Shreyas Kolapkar

Dissertations, Master's Theses and Master's Reports

Waste generation is increasing, and a significant portion is being landfilled. In parallel, we are constantly pursuing cleaner fuels due to environmental and regulatory factors. To address both these challenges, torrefaction of wastes to produce clean fuels and feedstock for other thermochemical processes is one of the potential solutions. This work focuses on (a) fundamental understanding of the properties of un-torrefied and torrefied wastes and (b) development of a pilot-scale integrated torrefaction-extrusion system for converting fiber-plastic wastes to solid fuels.

In this study, a 60:40 fiber-plastic waste blend was used for performing extensive experiments on densified and un-densified wastes to …

Entertainment 721, Mark Hendricks, Noah John, Jadon Vanyo, Chelsea Payne

Williams Honors College, Honors Research Projects

The goal of this project was to design a luxury, aesthetically pleasing entertainment system with a TV lift mechanism that could be remote controlled. The design would also include a cooling cabinet for gaming systems, a remote locking system, and additional storage. Using a morphological chart and weighted decision matrix for each subsystem key features were determined to be included in the design. Several performance benchmarks were determined to accomplish the team’s design. Almost every benchmark was successful in the build of the first prototype. Several heat calculations and FEA analyses were performed on the system to ensure the success …

Jominy Hardenability Tester Redesign, Dennis Kopacz, Shadoe Beatty, Thomas Benenati, Jared Mclean, Matthew Yokosuk

Williams Honors College, Honors Research Projects

Our project is Redesigning a Hardenability Tester. The goal of this project is to figure out how to incorporate an intensive quenching system to the current design from last years group. An intensive quench is a new system that is safer to harden steel and it hardens steel more effectively than other quenching processes. This will be achieved through testing the initial design to make sure it is able to run. After that as a group we will take this system through a design process to introduce a safe process of intensive quenching to the tester.

Exploring A Platinum Nanocatalytic Microcombustion-Thermoelectric Coupled Device, Dylan Moore Mcnally

Theses and Dissertations

This work aimed to create a first-generation power device for eventual application to portable electronics. A platinum nanoparticle catalytic substrate was employed in a microcombustion-thermoelectric coupled (MTC) device for the purpose of chemical-to-electrical energy conversion. Multiple microcombustion reactors were designed, fabricated, and investigated. Most importantly, the reactor configuration was designed to accommodate thermoelectric generators (TEGs) for power production. Temperature studies with catalytic combustion of methanol-air fuel mixtures were used to evaluate the thermal power generation performance of each reactor. The final reactor design enabled ignition at room temperature with the ability to achieve repeat catalytic cycles upon subsequent exposure to …

A Study On Latent Thermal Energy Storage (Ltes) Using Phase Change Materials (Pcms) 2020, Ritvij Dixit

Masters Theses

The significant increase in energy requirements across the world, provides several opportunities for innovative methods to be developed to facilitate the storage and utilization of energy. The major energy demand is in the form of electrical energy for domestic as well as industrial sectors, a large part of which are the heating and cooling requirements. Appropriate utilization of thermal energy storage can effectively aid in reducing the electrical demand by storage and release of this thermal energy during peak hours.

Thermal Energy Storage using Phase Change Materials (PCMs) is an attractive method of energy storage, with a wide variety of …

Thermo-Fluid Characterizations Of The Powder-Bed Fusion Additive Manufacturing Processes Using Laser And Electron Beam, M Shafiqur Rahman

University of New Orleans Theses and Dissertations

The powder-bed fusion (PBF) process is a subdivision of Additive Manufacturing (AM) technology where a heat source at a controlled speed selectively fuses regions of a powder-bed material to form three-dimensional (3-D) parts. Two of the most effective PBF processes are selective laser melting (SLM) and electron beam additive manufacturing (EBAM), which can fabricate full-density metallic parts in a layer-by-layer fashion. In this study, thermal behavior and melt-pool dynamics in the PBF process are investigated by developing 3-D multiphysics-based thermo-fluid models for both SLM and EBAM, containing Ti-6Al-4V alloy as a powder-bed material. The laser and electron beams are modeled …

Performance Improvements For Next Generation Falling Particle Receiver Systems, Nathan R. Schroeder

Mechanical Engineering ETDs

Falling particle receiver (FPR) systems are a rapidly developing technology for concentrating solar power applications. Solid particles are used as both the heat transfer fluid and thermal energy storage media. Through the direct solar irradiation of the solid particles, flux and temperature limitations of tube-bundle receives can be overcome leading to higher operating temperatures and energy conversion efficiencies. Particle residence time, curtain opacity, and curtain stability affect the performance of FPR designs. As the particles fall through the receiver the curtain accelerates, increasing its transmissivity thus decreasing the amount of energy absorbed. Multistage release trough structures catch and release the …

Development Of A Tiny House Design Tool To Increase Safety, Efficiency, And Cost-Effectiveness, Michael Joseph Stratton Ii

Masters Theses

A growing number of people are choosing to live more sustainably, and this is commonly done through living in an extremely small house, also called a “tiny house”. There is no set definition for a tiny house, but it typically refers to a structure less than 500 ft2, sometimes built by the homeowner, and frequently built on a travel trailer.

The popularity of tiny houses has increased over the years due to different television shows, internet videos, and photo sharing websites, but the technical details are rarely covered, which is why this study examines the structural, stability, weight, and thermal …

A Method For Developing And Testing Nuclear Reactor Systems With Space Applications And Improving Performance Of Heat Pipe Reactor Systems, David Duff Dixon

Doctoral Dissertations

The concept of using nuclear reactor technology in propulsion systems is nearly as old as nuclear reactors themselves. Numerous publications, many at very primitive conceptual levels, suggested nuclear propulsion in the 1940s. Since then, numerous attempts have been made to build and fly a nuclear rocket, yet there have been no such systems advanced to the point of a system test in more than half a century.

This dissertation presents an approach to reactor system development, a testing approach developed by the author that resulted in the operation of the world’s first heat pipe reactor system, and the world’s first …

Molecular Mechanisms And Design Of Hydrogen-Bonded Materials For Thermal Applications, Jinlong He

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Heat transfer at the nanoscale plays an important role in determining the reliability and performance of many innovative advanced materials technologies such as nanoelectronics, semiconductor, biomedical devices, polymers, and composites. Extensive efforts have been made to design materials with extraordinary thermal properties. However, fundamental understanding of heat transfer in many of these materials is still not lacking, because the thermal transport processes are governed by several factors including molecular morphology and chemical bonding. Among these factors, the atomic bonding between two dissimilar materials or within single materials is of particular interest due to its ubiquity and importance in physical processes. …

Heat Transfer Modeling And Optimization Of A Carbonized Microvascular Solar Receiver, Taylor Brown

Boise State University Theses and Dissertations

Concentrating solar power is an emerging renewable energy source. The technology can collect and store thermal energy from the sun over long durations, generating electricity as needed at a later time. Current CSP systems are limited to a maximum operational temperature due to constraints of the working fluid, which limits the maximum possible efficiency of the system. One proposed pathway forward is to utilize a gas phase for the working fluid in the system such as supercritical carbon dioxide.

A composite gas phase modular receiver is being developed by researchers at Boise State University and the University of Tulsa. The …

Effect Of Adding Palm Fiber To Thermal Conductivity Of Quick Set Concrete, Monica Garcia

Theses and Dissertations

As climate change becomes a more dire issue and more readily accepted by those in power, the demand for local and systemic solutions grows louder. In urban environments, one issue of concern is the contribution of anthropogenic heat from buildings which contributes to localized warming of the environment. A method that can reduce anthropogenic heat is decreasing the thermal conductivity of building materials. The objective of this study is to examine the possibility of using palm fibers to reduce the thermal conductivity of quick-set concrete samples. The data gathered in this study are used to determine the thermal conductivity value …

Numerical Modeling And Conjugate Heat Transfer Analysis Of Single U-Tube Vertical Borehole Heat Exchangers, Talha Khan

FIU Electronic Theses and Dissertations

The primary purpose of this thesis was to develop a design for improving the efficiency of the vertical type single u-tube borehole heat exchanger. A thorough literature review of the various existing analytical and numerical models of the borehole heat exchanger (BHEs) was performed and numerical modeling of the BHE was conducted to solve the conjugate heat transfer problem in the BHE in 3D using ANSYS Fluent 2019 R1. A comparison between the results obtained using various mesh sizes, types, different turbulence models showed the independence of the parameters on the numerical simulation results.

From the numerical simulation, it was …

Characterization For Spray Droplet Behaviour In Afterburner-Like Flow Conditions, Matthew D. Mahaffy

Electronic Thesis and Dissertation Repository

Fuel injection processes can contribute to combustion instability in highly energetic combustion systems. In gas turbine engine afterburners, jet-in-crossflow (JIX) injection is used. Part one of the thesis study investigates the interaction between spray droplets and turbulent flow properties of a JIX. Jet-in-counterflow (JIC) configuration was also investigated. Part two of the investigation examined the behaviour of JIX droplets around a bluff body. Droplet size and flow turbulence was characterized simultaneously using particle image velocimetry and image processing techniques. Turbulence and droplet size were correlated, particularly at momentum flux ratios ≥ 60. High speed imaging was used to identify droplet …

Sustainable Smouldering For Waste-To-Energy: Scale, Heat Losses, And Energy Efficiency, Tarek L. Rashwan

Electronic Thesis and Dissertation Repository

Applied smouldering combustion is emerging as a highly energy efficient approach towards waste-to-energy. This thesis aims to better understand this potential by addressing a critical knowledge gap between laboratory scale smouldering research and large-scale applications. Altogether, new understanding in provided on the complex and dynamic interactions between the reaction zone (smouldering front) and the cooling zone (treated inert porous media) by integrating theory, experiments, analytical modelling, and global energy balance calculations. The experiments spanned a range of reactor sizes and smouldering conditions (from weak to robust) with dry (carbon) and wet (sludge) fuels mixed in sand. This work revealed that …

Modeling, Simulation, And Testing Of Sweeping Convection, Amir Kiaee

Mechanical Engineering Research Theses and Dissertations

In this study, the new convection heat transfer concept of sweeping convection, using large particles flowing with a fluid in a channel, is considered. This novel concept is inspired by the gas exchange process in alveolar capillaries, where red blood cells (RBCs) flow with blood plasma, yielding very high gas transfer efficiency. An important characteristic of alveolar capillary blood flow, believed to be related to the high efficiency of the lungs, is the snug fitting of the RBCs into the capillaries. This tight fitting sets the RBCs (particles) acting like pistons as they flow downstream with the plasma (fluid), facilitating …

Thermal Control Development Of A Proton Exchange Membrane Fuel Cell System, Ola Mohammed Taha Al-Shalash

Mechanical Engineering Theses

A fuel cell is an electrochemical energy conversion device that uses fuel to generate electricity. It basically converts the chemical energy of reactants directly into electricity without combustion. In a Proton Exchange Membrane Fuel Cell (PEMFC), the reactants, hydrogen and oxygen, are fed into the two electrodes, anode and cathode, respectively. A reaction takes place at each electrode and produces electricity, as well as water, and heat as the by-products. In order to maximize performance of a fuel cell, many factors can be considered for tuning and control. Temperature management is one of these factors.

A thermal-fluid model of a …

Potential Energy Generation From Agricultural Residue In Indonesia, Adrian Rizqi Irhamna

English Language Institute

Indonesia has great potential of biomass sources from their agricultural residue, which can potentially be used for alternative energy generation. This preliminary research explores the most suitable technology for energy generation from agricultural residue and its challenge for application in Indonesia. The study showed that biomass utilization via the direct combustion process is recommended for energy generation. It is also reported that the pretreatment process of drying and washing, are required to increase the fuel quality and plant efficiency.

Cooking Systems Using Aluminum Foam, Ryan Tetsuo Mizukami

Physics

In developing countries, the use of wood burning fires for cooking is cause for illness and death. With this in mind, research was conducted to develop a solar cooking device capable of cooking of soup within 15 mins in order to reduce the negative impacts of cooking with wood. Current methods of solar-based cooking, such as solar concentrators and solar tube ovens, are impractical. A small solar panel is a cost-effective way to produce energy but will not produce enough power to cook within a reasonable amount of time. Even if it is assumed that all of the energy produced …