Heat Transfer, Combustion Commons^™

Numerical Simulations Of Premixed Flames Of Multi Component Fuels/Air Mixtures And Their Applications, Essa Kh I J Salem

Theses and Dissertations--Mechanical and Aerospace Engineering

Combustion has been used for a long time as a means of energy extraction. However, in the recent years there has been further increase in air pollution, through pollutants such as nitrogen oxides, acid rain etc. To solve this problem, there is a need to reduce carbon and nitrogen oxides through lean burning, fuel dilution and usage of bi-product fuel gases. A numerical analysis has been carried out to investigate the effectiveness of several reduced mechanisms, in terms of computational time and accuracy. The cases were tested for the combustion of hydrocarbons diluted with hydrogen, syngas, and bi-product fuel in …

Elevated Temperature Progressive Damage And Failure Of Duplex Stainless Steel, Darren P. Luke

Civil Engineering ETDs

Ductile failure of metals has been the focus of research efforts within academia and industry for many years since it is tremendously important for understanding the failure of structures under extreme loading conditions. However, limited research has been dedicated to elevated temperature ductile failure, which is critical for evaluating catastrophic events such as industrial, structural or shipping vessel fires. A detailed investigation was conducted on the structural response of Duplex Stainless Steel at elevated temperatures. The temperature dependence of elastic modulus, yield strength, ultimate strength, and ductility was measured up to 1000°C and a continuum damage plasticity model was developed. …

Experimental Investigation Into The Effects Of Thermal Recuperation On The Combustion Characteristics Of A Non-Premixed Meso-Scale Vortex Combustor, Seyed Ehsan Hosseini, Evan Owens, John Krohn, James Leylek

Faculty Publications - Mechanical Engineering

In small-scale combustors, the ratio of area to the combustor volume increases and hence heat loss from the combustor’s wall is significantly enhanced and flame quenching occurs. To solve this problem, non-premixed vortex flow is employed to stabilize flames in a meso-scale combustion chamber to generate small-scale power or thrust for propulsion systems. In this experimental investigation, the effects of thermal recuperation on the characteristics of asymmetric non-premixed vortex combustion are studied. The exhaust gases temperature, emissions and the combustor wall temperature are measured to evaluate thermal and emitter efficiencies. The results illustrate that in both combustors (with/without thermal recuperator), …

Portable Thermoelectric Refrigerator, Cassandra Danielle Beck, Ryan Theodore Gelinas, Joshua Michael Dimaggio, Zachary David Wilson

Mechanical Engineering

This project created a versatile thermoelectric refrigerator that can be used via a wall outlet. The product is durable and effective. The refrigerator is functional in any ambient temperature, and uses thermoelectric cooling, and work from a standard 120V power outlet. By understanding existing products’ limitations and strengths, this project produced a product that outperforms what’s currently on the market. Many of the existing products’ operating temperature is dependent on the ambient temperature of the surroundings, which is a large drawback. Additionally, most of them take a long time to reach their lowest temperature, around 3 hours. One team member, …

Optimization Of Analytical Inverse Heat Transfer Recovery Solution, Nathan Schick

Masters Theses

This thesis describes the different methods used when trying to solve inverse heat transfer problems, particularly those involving recovering heat flux. There are currently several techniques to measure the temperature history in an object subjected to heat transfer using various temperature sensors, however these types of sensors are gradually being replaced by Temperature Sensitive Paints (TSP), a technique that is more accurate and provides a better spatial resolution. TSP is a polymer that is applied on a base object. Changes in temperature in the polymer result in variations of the luminescence intensity in the paint. These variations can be captured …

Effect Of Aerogel On The Thermal Performance Of Corrugated Composite Sandwich Structures, Jacob Dillon Chess

Master's Theses

Current insulation solutions across multiple industries, especially the commercial sector, can be bulky and ineffective when considering their volume. Aerogels are excellent insulators, exhibiting low thermal conductivities and low densities with a porosity of around 95%. Such characteristics make aerogels effective in decreasing conductive heat transfer within a solid. These requirements are crucial for aerospace and spaceflight applications, where sensitive components exist among extreme temperature environments. When implemented into insulation applications, aerogel can perform better than existing technology while using less material, which limits the amount of volume allocated for insulation. The application of these materials into composites can result …

Liquid-To-Liquid Low Grade Waste Heat Recovery Using A Two-Channel Loop, Waleed Farwana

Masters Theses

The use of thermoelectric generators (TEGs) for producing electric energy from low grade “waste heat” has been theorized to provide a sustainable and low-cost energy source for electric power plants. The purpose of this study is to model and experimentally validate a TEG device that takes advantage of low grade waste heat (approximately 100-150 degrees Celsius) in liquid form in order to generate power that can be used for various applications in the surrounding environment. This research aims to demonstrate that optimized TEG designs bear the potential to compete with other methods of low grade waste heat energy harvesting in …

Optimization Of The Practice Of Slow Cooling Steel Bars: A Redesign And Modernization Of Materials, Eryn Johnston

Mechanical Engineering Undergraduate Honors Theses

Throughout the process of steel making, certain grades of steel are a higher risk for defects caused by the inability to quickly diffuse hydrogen through the steel when cooled to room temperature at a normal rate based on the ambient air temperature. To reduce the hydrogen flaking defects that are caused due to hydrogen entrapment in the steel, the process of slow cooling is utilized. This process reduces the cooling rate of steel bars by keeping them at a higher temperature for extended periods and in turn gives the hydrogen a chance to fully dissipate from the steel. In many …

Process-Property-Microstructure Relationships In Laser-Powder Bed Fusion Of 420 Stainless Steel., Subrata Deb Nath

Electronic Theses and Dissertations

Laser-powder bed fusion (L-PBF) is an additive manufacturing technique for fabricating metal components with complex design and customized features. However, only a limited number of materials have been widely studied using L-PBF. AISI 420 stainless steel, an alloy with a useful combination of high strength, hardness, and corrosion resistance, is an example of one such material where few L-PBF investigations have emerged to date. In this dissertation, L-PBF experiments were conducted using 420 stainless steel powders to understand the effects of chemical composition, particle size distribution and processing parameters on ensuing physical, mechanical and corrosion properties and microstructure in comparison …

Low Temperature Desiccants In Atmospheric Water Generation., Sunil Gupta

Electronic Theses and Dissertations

Surging global water demand as well as changes to weather patterns and over exploitation of natural water sources, such as ground water, has made potable water a critical resource in many parts of the World already – one rapidly heading towards a crisis situation. Desalination has been adopted as a solution – this is however energy intensive and impractical for most of the developing countries - those most in need of water. A renewable source of energy is solar thermal and solar photovoltaic. A plentiful source of water is the humidity in the atmosphere. This research is to push the …

A Systematic Investigation Of Condensation Heat Transfer Using Asymmetric Micro-Scale Surfaces, Emily Brown

LSU Master's Theses

Asymmetric surfaces been shown to inducing unidirectional motion in the Leidenfrost regime; however, very minimal research has been conducted to investigate whether these surface can enhance condensation through the same means. The investigation of heat transfer of ratchets in condensation is a relatively untapped area of study, specifically ratchets with superhydrophobic properties. Anticipated difficulty lies in creating surfaces features or coatings that retain the ratchets and can adequately sustain optimal wetting state of Cassie-Baxter required to improve heat transfer performance during condensation. This study serves to investigate whether ratchets are a feasible surface feature to enhance condensation heat transfer. First, …

Large Eddy Simulations Of Vertical Jets In Crossflow, Pranaya Pokharel

LSU Doctoral Dissertations

Jets in crossflow (JICF) have applications ranging from oil spill to film cooling of turbine blades. Hence, an understanding of the flow physics is important. The majority of the research has been conducted for low velocity ratios between jet and crossflow with round jets. JICF is demonstrated to behave differently for high velocity ratios and different jet shapes. Circular and rectangular jets are commonly used in aircraft applications. Current study focuses on high velocity ratio JICF issuing from both circular and rectangular exit.

For simulating JICF, an in house code “Chem3D” is used with Large Eddy Simulation (LES) to model …

Combustion Dynamics And Heat Transfer In An Ultra Compact Combustor, Brian T. Bohan

Theses and Dissertations

The Ultra Compact Combustor (UCC) is an innovative combustion system alternative to a traditional turbine engine burner with the potential to improve engine efficiency with a reduced combustor volume. The UCC shortens the axial length of the combustor, and therefore reduces engine weight, by burning in an annulus and swirling the reactants in the circumferential direction. These length and weight improvements can directly lead to an increased thrust-to-weight rating of the engine. The present research included five objectives which advanced the UCC concept on four fronts; cooling UCC turbine vanes, advanced computational modeling of UCC systems, system air split control …

Micro Combustion Of Primary Reference Fuels In Narrow Heated Channels, Veerendra Naralasetti

LSU Master's Theses

Conventional fuel testing machines like CFR engines require large quantities of fuel. The current study seeks to overcome this limitation by introducing an alternative method using a microscale combustion reactor which consumes relatively small amounts of fuel (100-250 ml). For this reason, Primary Reference Fuels (PRF’s: volumetric mixtures of n-heptane and iso-octane) which are simple surrogates of gasoline are selected to test using micro reactor. The primary goal is to determine the effectiveness of using the micro reactor setup to differentiate fuels of different octane number. Experiments with stoichiometric PRF/air mixtures are performed inside a cylindrical quartz tube of 1mm …

Waste Heat Recovery From A Vented Electric Clothes Dryer Utilizing A Finned-Tube Heat Exchanger, Abdul Raheem A. Shaik, Stephen L. Caskey, Eckhard A. Groll

The Summer Undergraduate Research Fellowship (SURF) Symposium

Conventional residential clothes dryers continuously vent moist, hot air during the drying process. The vented air leaves the home but still has useful temperature and humidity that could be recovered to offset other heating demands in the home. A study is carried out to quantify the amount of heat extracted from the waste heat stream of a conventional, vented clothes dryer. To extract the heat, a water cooled, fin-and-tube heat exchanger is located within the exhaust duct. A steady state thermodynamic dry coil and wet coil model was built in Engineering Equation Solver (EES). The model accounts for the heat …

Thermophotovoltaic Devices: Combustion Chamber Optimization And Modelling To Maximize Fuel Efficiency, Arnold Chris Toppo, Ernesto Marinero, Zhaxylyk Kudyshev

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, 110 billion cubic meters of natural gas (primarily methane), a potent greenhouse gas, are flared off for environmental and safety reasons. This process results in enough fuel to provide the combined natural gas consumption of Germany and France. The research team developed a thermophotovoltaic device to convert thermal energy to electricity at a high efficiency using proprietary emitters and combustion system. With the current focus being fuel efficiency and the combustion process, the assembly was simulated using ANSYS Fluent modelling software and the following parameters were optimized: air/fuel ratios, flow rates, and inlet sizes. Simultaneously the heat transfer across …

Study Of The Effective Thermal Conductivity Of Polymer Composites With Varying Filler Arrangements, Debraliz Isaac Aragones, Rajath Kantharaj, Aaditya Candadai, Amy Marconnet

The Summer Undergraduate Research Fellowship (SURF) Symposium

Alternative thermal management solutions for electronic devices are being widely explored due to the increasing heat concentration that results from shrinking sizes and increasing power of modern electronics. Clearly, there is a need to spread the heat effectively in these systems, and polymer composites can potentially provide high thermal conductivity at low filler fraction while maintaining desirable mechanical properties for electronic packaging. The present study aims to investigate the effective thermal conductivity of various copper filler arrangements in a polymer matrix. The polymer composites are fabricated using laser cut acrylic templates to embed aligned copper rods in epoxy and create …

Selecting The Most Effective Energy Modeling Tool Based On A Project Requirement, Sodiq Akande

Electronic Theses and Dissertations

Building energy usage can be derived and controlled by performing building energy modeling. BEM can be performed using numerous software tools such as DesignBuilder, OpenStudio, EnergyPlus etc. These modeling tools can be sorted into three different modeling categories: Black-box, Gray-box and White-box. It is important for a modeler to be able to quickly select the proper tool from the proper category to meet the need of the project. To validate the method of categorizing tools, the three models generated using tools from each category and the modeling outputs required were compared. Each model was designed to estimate the amount of …

What Can I Do As A Student To Make A Positive Impact On The Environment?, Tammy Guthrie, Greg Herzig, Kathy Prophet, Cassie Kautzer

Middle School Lesson Plans

Students discover ways they can make a positive impact on the environment.

3d Numerical Study Of Multiphase Counter-Current Flow Within A Packed Bed For Post Combustion Carbon Dioxide Capture, Li Yang, Fang Liu, Zhengchang Song, Kunlei Liu, Kozo Saito

Mechanical Engineering Faculty Publications

The hydrodynamics within counter-current flow packed beds is of vital importance to provide insight into the design and operational parameters that may impact reactor and reaction efficiencies in processes used for post combustion CO₂ capture. However, the multiphase counter-current flows in random packing used in these processes are complicated to visualize. Hence, this work aimed at developing a computational fluid dynamics (CFD) model to study more precisely the complex details of flow inside a packed bed. The simulation results clearly demonstrated the development of, and changes in, liquid distributions, wetted areas, and film thickness under various gas and liquid …

Transient Heat Storage Systems, Ian M. Sweeney, Brock M. Johnson, Todd K. Lundberg

Mechanical Engineering

Phase change materials (PCM) have many applications in transient cooling systems, including those with high transient heat loads and low duty cycles. These materials allow a system to remain within a narrow temperature range with a relatively low weight compared to conventional heat sinks or high-power cooling systems. This senior capstone project includes the design of a PCM based thermal energy storage system to integrate into an existing cooling loop, as well as a determination of viable PCM’s for the application. This report contains the necessary information to build the test apparatus.

Driver Cooling System, Joseph Fatin Bolous, Jake Donald Deboer, Alvin Theodore Lau

Mechanical Engineering

This document provides our Final Design Review (FDR) for the Driver Cooling System Project. It contains our background research, which includes current product research, technical research, and information on our sponsor’s needs as a customer as well our manufacturing process, test results, and final design. We created a problem statement to define the scope of the project, discuss sponsor and consumer needs and wants, and technical specifications. After brainstorming, we ultimately selected a thermoelectric cooling system (TEC) after presenting our Preliminary Design Report and Critical Design Report. We built the final prototype, as can be seen in the manufacturing plan, …

3-Dimensional Automated Heat Flux Calibration Device, Victor Raul Chacon, David Madison Morrisset, Alex Michael Schnorr, Kevin Scott

Mechanical Engineering

This document aims to describe the problems in current radiant heat source heat flux calibration techniques and the approach our team took to solve them through automation. The following sections outline the basic premise of the problem we addressed and who our end product benefited. The proceeding sections addresses the research that we have performed regarding heat flux measurements and automation. This research includes current solutions – mostly partial solutions for problems that are similar but not exactly like ours. Following the background research, we define objectives, with specific details that outline how we evaluated different possible solutions, and how …

Upgrading The Sr-30 Miniature Turbojet For Adaptable Exhaust, Shannon Ferreira, Erin Mcmurchie, Peter Pratt

Mechanical Engineering

The California Polytechnic State University, San Luis Obispo (Cal Poly, SLO) Aerospace Department is requesting a variable nozzle adaptation for their SR-30 turbojet engine. The nozzle is intended for laboratory use in sophomore and junior level courses to supplement instruction on the effects that exhaust behavior has on the performance of propulsion technologies. Topics covered during a performance study of the SR-30 turbojet engine will include, but are not limited to: Brayton Cycle analysis, turbojet operation in ideal and non-ideal test conditions, instrumentation limitations, and basic nozzle operation. The SR-30 turbojet engine is similar in design and operation to engines …

Heat Flow Characterization Of Speakers, Sabrina M. Gough, Lydia K. Hedge, Nicolas M. Jones

Mechanical Engineering

Statement of Confidentiality: The complete senior project report was submitted to the project advisor and sponsor. The results of this project are of a confidential nature and will not be published at this time.

Bubble Nucleation In Superhydrophobic Microchannels Due To Subcritical Heating, Adam Cowley, Daniel Maynes, Julie Crockett, Brian D. Iverson

Faculty Publications

This work experimentally studies the effects of single wall heating on laminar flow in a high-aspect ratio superhydrophobic microchannel. When water that is saturated with air is used as the working liquid, the non-wetted cavities on the superhydrophobic surfaces act as nucleation sites and allow air to effervesce out of the water and onto the surface when heated. Previous works in the literature have only considered the opposite case where the water is undersaturated and absorbs air out the cavities for a microchannel setting. The microchannel considered in this work consists of a rib/cavity structured superhydrophobic surface and a glass …

Finite-Difference Modeling Of The Batch Process Smoldering Combustion Of Wastewater, Laura H. Kawashiri

Master's Theses

A MATLAB model was developed for the smoldering combustion of wastewater in the context of a decentralized residential wastewater treatment appliance. Data from a batch process sewage smoldering experiment was simulated using implicit finite-difference approximations, assuming one-dimensional transient conductive heat transfer. The time-dependent temperature profiles within the column represented the main parameters of interest and were used to verify recoverable heat energy estimations. Given that the modeling method used for this thesis represents a unique approach, the assumptions and limitations of this model are thoroughly described in the context of reproducing results for other smoldering setups. A lack of convergence …

Thermal Modelling And Validation Of Heat Profiles In An Rf Plasma Micro-Thruster, Alec Sean Henken

Master's Theses

The need and demand for propulsion devices on nanosatellites has grown over the last decade due to interest in expanding nanosatellite mission abilities, such as attitude control, station-keeping, and collision avoidance. One potential micro-propulsion device suitable for nanosatellites is an electrothermal plasma thruster called Pocket Rocket. Pocket Rocket is a low-power, low-cost propulsion platform specifically designed for use in nanosatellites such as CubeSats. Due to difficulties associated with integrating propulsion devices onto spacecraft such as volume constraints and heat dissipation limitations, a characterization of the heat generation and heat transfer properties of Pocket Rocket is necessary. Several heat-transfer models of …

Temperature And Stress Analysis During Tank Decanting And Refilling Process, Zhe Liu

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

In the present work, an analytical expression for the temperature distribution of the cross-section of a natural gas transport tank is derived by time-matching Green’s Function method. The tank decanting process can produce a living temperature decrease inside the tank wall while the filling process can produce a large temperature increase. This behavior can cause damage to the inner layer of the tank. The damage occurs in the form of excessive stress in the wall which is combined mechanical stress and thermal stress. Therefore, thermo-elasticity analysis is another objective of the present work. A simplified mechanical model is established in …

Experimental And Numerical Comparison Of Wort Cooling Methods During The Homebrewing Process, Zachary Hammond

Renée Crown University Honors Thesis Projects - All

Homebrewing, the process of making beer for personal consumption, has been legal in the United States since 1978 and allowed beer enthusiasts to experiment with new beer styles at a low cost. Although the procedure is relatively straightforward, it can be very timeconsuming without expensive equipment. The longest step in brewing is wort cooling, where the non-alcoholic beer, or wort, is cooled from boiling temperatures to near room temperature for fermentation. Improper or slow cooling can not only be monotonous but result in contamination or haze in the final product. Wort chillers, which generally cost anywhere from $50 to $500, …