Heat Transfer, Combustion Commons^™

Rocket Motor Nozzle, Corey Hillegass

Williams Honors College, Honors Research Projects

For this honors research and senior design project, the authors will research, analyze, and manufacture a rocket motor nozzle for the Akronauts rocket design team. This research and design project will improve how the rocket design team will decide and manufacture nozzles going forward. The impact of this improvement allows the rocket design team to take steps toward being self-sustaining by manufacturing student designed parts as opposed to commercially bought parts. This will not only be successful in increasing student impact on future designs, but also provides a technical challenge for the authors and will present as an impressive feat …

Zips Precious Plastics: Plastic Extruder, Patrick Cole

Williams Honors College, Honors Research Projects

This project's goal was to design and build an affordable desktop filament extruder that can precisely and consistently extrude filament to a certain tolerance acceptable for 3D printers using wasted printing material. The group is partnering with an on campus organization focusing on engineering applications for sustainable futures. Zips Precious Plastics is a student run design group that intends to bring an innovation space on campus to help educate students about the importance of a closed looped system within plastic manufacturing.

Non-Linear Non-Iterative Transient Inverse Conjugate Heat Transfer Method Applied To Microelectronics, David Gonzalez Cuadrado, Amy Marconnet, Guillermo Paniagua

CTRC Research Publications

Solving for temperature profiles given boundary conditions, geometry, and material properties is rela- tively straightforward given the wealth of analytical and computational techniques available. However, experimentally we often measure temperatures and seek to understand unknown boundary conditions or material properties. This problem is generally ill-posed. Thus, to get the value of these input param- eters, we use inverse methods: knowing the output of the system ( i.e. , temperature), we can compute the value of the unknown parameters ( e.g. , thermal conductivity or heat fluxes). In microelectronics, the location and magnitude of the boundary conditions including local heat generation …

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 …

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 …

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 …

Efficient Enhancement Of Micro-Nucleation Rates In Flow-Boiling - By Concurrent Micro-Structuring Of The Boiling-Surface And Its Judicious Energization By Piezoelectric-Transducer Induced Acoustic Vibrations., Atharva Rahane

Dissertations, Master's Theses and Master's Reports

The report describes the science and technology backgrounds and uses for the technology breakthrough reported for enhanced flow-boiling based cooling of high-power density electronics (chips, memory etc.). A controlled but explosive growth in micro-scale nucleation rates during flow-boiling of HFE-7100 (electronics and environment friendly liquid from 3M, Inc) is enabled by the uses of inexpensive meshed-copper for micro-structuring of the boiling surface and a pair of Piezoelectric-transducers for active imposition of suitable acoustic vibrations. The pair of piezo transducers mounted just outside the mini-channel impose “in plane” acoustic vibrations of controllable amplitudes and frequencies, and they are used to induce …

Energetic And Exergetic Analysis Of A Heat Pipe Evacuated Tube Solar Collector Using Mwcnt/Water Nanofluid, Mahmoud Eltaweel, Ahmed A. Abdel-Rehim

Mechanical Engineering

Increasing the energy demand and the limited availability of conventional energy sources are the main challenges to secure the human future. Solar energy is an attractive source of energy to ensure the sustainability of energy in this world for now and for the future. Evacuated tube solar collector is a solar thermal collector mostly used for domestic applications. The replacement of the working fluid with nanofluid can enhance the heat transfer even for low temperature applications. The effect of multi-walled carbon nanotubes and water nanofluid as working fluid in evacuated tube solar collector is used to experimentally investigate the energy …

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 …

Experimental, Computational And Analytical Studies Towards A Predictive Scenario For A Burning Accident, Furkan Kodakoglu

Graduate Theses, Dissertations, and Problem Reports (ETD)

Historically, accidental gas and dust explosions constitute one of the major hazards to both personnel and equipment in the process industries. The current knowledgebase on such explosions does not provide an acceptable level of risk. Therefore, novel preventive mining/fire safety strategies, based on a rigorous predictive scenario for burning accidents, are critically needed. The present dissertation is devoted to such a predictive scenario, with a particular focus on the flame and pressure evolutions in explosions encountered in an enclosure with or without obstructions. The experimental component of this dissertation comprises a series of experiments on explosion venting. Specifically, the influence …

Towards Large Eddy Simulation Of A Staged, Pressurized Oxy-Fuel Combustor, Alain Islas Montero

Graduate Theses, Dissertations, and Problem Reports (ETD)

Identified by the DoE among the novel and transformational technologies, staged-pressurized oxy-fuel combustion (SPOC) is a promising low-cost, low-emission, and highly efficient tool for carbon capture utilization and storage (CCUS), with pulverized coal burning under elevated pressures and low recycled flue gas. A lab-scale SPOC facility, under establishment at Washington University in St. Louis (WUSTL), causes the critical need to develop accurate and reliable computational models to assist the ongoing WUSTL experiments. This constitutes the driving motivation of the present work. Specifically, comprehensive three-dimensional Large-eddy simulations (LES) of the lab-scale SPOC reactor, with most of important characteristics of a multi-phase …

Development Of An Activity-Based Windowing Approach To Evaluate Real-World Nox Emissions From Modern Medium And Heavy-Duty Diesel Trucks, Rasik Pondicherry

Graduate Theses, Dissertations, and Problem Reports (ETD)

The introduction of in-use emissions regulations by the United States Environmental Protection Agency (U.S.EPA) requires medium-duty (MD) and heavy-duty (HD) engine manufacturers to demonstrate emissions compliance during in-fleet operation. In the United States (U.S.), the Not-to-Exceed (NTE) method is used to evaluate real-world emissions compliance from on-highway MD and HD trucks. Regulatory agencies, engine manufacturers and research entities have identified that the NTE method incorporates numerous exclusions and evaluates emissions compliance only under selective operating conditions that are favorable for the selective catalytic reduction (SCR) system to reduce oxides of nitrogen (NOx) emissions efficiently. Such operation is typically encountered only …

Characterizing Premixed Syngas Combustion In Micro-Channels, Sunita Pokharel

Graduate Theses, Dissertations, and Problem Reports (ETD)

Increasing demands in the next-generation portable power-generation devices such as unmanned aerial vehicles (UAV), microsatellite thrusters, micro-chemical reactors and sensors calls for fuels with high specific energy and low emissions to meet the current demand of green energy. Fuel-lean synthesis gas (syngas) meets both these requirements exhibiting a promising route to a clean and green environment. Thus, it is of critical importance to characterize syngas combustion and understand its properties in the micro-combustion industry. In addition to complicated flame dynamics in microscale systems, varying the syngas-fuel mixture composition as well as the boundary conditions and geometry of a combustor significantly …

Fully Compressible Hydrodynamic Simulation Of Non-Equidiffusive Premixed Flames Propagation In Channels, Olatunde A. Abidakun

Graduate Theses, Dissertations, and Problem Reports (ETD)

Premixed combustion remains of fundamental interest in energy generation and propulsion systems as well as in implementation of safety measures for residential and industrial accidental fire explosions. While the fast pace and complex nature of the combustion process has previously necessitated the analytical and computational studies to employ the simplifying assumption of equidiffusivity, when the Lewis number defined as the thermal-to-mass diffusivities ratio is unity , the ongoing advancements in technology and the requirements for efficiently operating combustors over a wide range of conditions make the combustion process more non-equdiffusive ( ) than ever. The impact of non-equidiffusivity on the …

Enhanced Heat Transfer Performance By Shape Optimization Of A Non-Axisymmetric Droplet Evaporating On A Heated Micropillar, Haotian Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Abstract

Enhanced Heat Transfer Performance by Shape Optimization of a Non-axisymmetric Droplet Evaporating on a Heated Micropillar

By

Haotian Wu

Department of Mechanical Engineering and Materials Science

Washington University in St. Louis, 2019

Research Advisor: Professor Damena Agonafer

The stacked multilayer 3D IC structure used in next generation high-powered electronics poses great challenges in dissipating their large heat flux, which causes extreme difficulties for traditional cooling technologies. In response, more advanced two-phase liquid cooling technologies, such as droplet evaporation, which utilizes the latent heat of vaporization to remove excessive heat, have been widely investigated. Compared to traditional single-phase cooling techniques, …

The Investigation Of Noise, Vibrations And Emissions Of Aero-Gas Turbine Combustion With Synthetic Kerosene Fuels, Margaret Kilpatrick

Honors College Theses

Climatic changes from aviation emissions are complex and include effects of greenhouse gases such as: CO2, NOx, and aerosols. For that reason, the objectives of this study were to investigate the noise, vibrations and emissions characteristics of synthetic kerosene combustion in an aerospace gas turbine to reduce the engine’s environmental impact. Sustainably produced synthetic kerosene is known for having low soot emissions due to little to no aromatics (compounds that create particle pollutants), and for being a sustainable alternative fuel source to imported oil. The noise and sound levels were collected using Bruel & Kjaer microphones to measure various mid …

Thermodynamic Model Of Co2 Deposition In Cold Climates, Sandra K. S. Boetcher, Ted Von Hippel, Matthew J. Traum

Publications

A thermodynamic model, borrowing ideas from psychrometric principles, of a cryogenic direct-air CO2-capture system utilizing a precooler is used to estimate the optimal CO2 removal fraction to minimize energy input per tonne of CO2. Energy costs to operate the system scale almost linearly with the temperature drop between the ingested air and the cryogenic desublimation temperature of CO2, driving siting to the coldest accessible locations. System performance in three Arctic/Antarctic regions where the proposed system can potentially be located is analyzed. Colder ambient temperatures provide colder system input air temperature yielding lower CO2 removal energy requirements. A case is also …

Waste Gasification, Glyn D. Lewis, Nash Taylor, Nicholas L. Ordonez, David S. Mccallum

Mechanical Engineering

This document summarizes the work the IGT Team has conducted on the topic of waste to energy gasification over the Cal Poly Winter, Spring, and Fall quarters of 2019. The project is being carried out by four Cal Poly Mechanical Engineering students: Nash Taylor, Glyn Lewis, David McCallum, and Nicholas Ordonez and the sponsor of this project is Tod duBois. The team’s original goal was to successfully create a system that compiles residential solid waste on a small scale, gasifies it, and measures the typical syngas outputs, so that the team may assess the viability of gasification of household waste …

Critical Radius Of Insulation, Maria N. Ambrose, Samuel J. Sayre, Travis W. Martin, Matt T. Sterling

Mechanical Engineering

The critical radius of insulation is a counterintuitive concept within the study of heat transfer. The theory states that adding insulation to a cylindrical or spherical object will increase the rate of heat loss rather than decrease it, if the radius (thickness) of the insulation is at its “critical” value. The Critical Radius of Insulation Senior Project is designed to demonstrate this phenomenon to Heat Transfer students via a portable apparatus. The concept will be demonstrated with a cylindrical object which is heated by way of a separate voltage source. Thermocouples will display the temperature of the cylinder while insulation …

Fabrication And Thermal Characterization Of Composite Cu-Cnt Micropillars For Capillary-Driven Phase-Change Cooling Devices, Gerardo Rojo, Siavash Ghanbari, Jeff Darabi

SIUE Faculty Research, Scholarship, and Creative Activity

This paper presents the fabrication, testing, and modeling of an array of composite copper-carbon nanotubes (Cu-CNT) micropillars as a wick structure for potential application in passive phase-change cooling systems. This novel wick structure has a larger spacing at the base of the micropillars to provide a higher liquid permeability and mushroom-like structures on the top surface of the micropillars with a smaller spacing to provide a greater capillary pressure. The composite Cu-CNT micropillars were fabricated by an electrochemical deposition method on a patterned copper template. Cauliflower-like nanostructures were then grown on the top surface of the micropillars using chronoamperometry technique …