Heat Transfer, Combustion Commons^™

Experimental Investigation Into The Effects Of Air Staging On Fouling In A Fixed-Bed Biomass Combustor, Akram Elsebaie

Theses: Doctorates and Masters

Biomass offers significant potential as a sustainable and renewable substitute for fossil fuels in energy generation, playing a critical role in the reduction of global warming. However, despite its environmental benefits, biomass combustion faces persistent operational challenges, particularly fouling, which reduces efficiency and increases maintenance costs. Although fouling mechanisms have been studied in various combustion systems, there is limited research which addresses its formation and behaviour in fixed-bed biomass combustors under different air staging conditions. This research investigates fouling behaviour in a counter-current combustor, focusing on the influence of design (secondary air location), operational (air staging flowrates between the primary …

Numerical Simulation Of The Donor-Assisted Stir Material For Friction Stir Welding Of Aluminum Alloys And Carbon Steel, Joseph Maniscalco, Abdelmageed A. Elmustafa, Srinivasa Bhukya, Zhenhua Wu

Mechanical & Aerospace Engineering Faculty Publications

In this research effort, we explore the use of a donor material to help heat workpieces without wearing the tool or adding more heat than necessary to the system. The donor material would typically be a small piece (or pieces) of material, presumably of lower strength than the workpiece but with a comparable melting point. The donor, a sandwich material, is positioned between the tool head and the material to be welded, where the tool initially plunges and heats up in the same manner as the parent material that is intended for welding. The donor material heats up subsequent to …

Exergetic Relationship Between The Thermal Properties Of Direct Contact Membrane Distillation, D. Perdue, L. Chen, L. Schaefer

Publications

Direct contact membrane distillation (DCMD) is a process that has shown promise within the field of desalination due to its less energy intensive methods and widespread applications. DCMD is a thermally driven microfiltration separation process that operates on the principle of vapor–liquid equilibrium conditions where heat and mass transfer occur simultaneously. Fundamentally, DCMD is based on a porous hydrophobic membrane separating the hot solution (feed) from the cold solution (permeate) where desalinated water condenses. The membrane interfacial temperatures determine the vapor pressure difference across the membrane. In this work, a direct simulation Monte Carlo analysis is employed to investigate how …

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. …

Numerical Simulations Of Transcritical Natural Convection, Ruiwen Wei, Carlo Scalo, Mario Tindaro Migliorino, Kukjin Kim, Jean-Pierre Hickey

The Summer Undergraduate Research Fellowship (SURF) Symposium

In modern engineering applications, system overheating is a key issue that needs to be solved with efficient and reliable cooling technologies. Among the possible mechanisms that these are based on, natural convection cooling is one of the most frequently employed, with applications ranging from cooling of computer micro-components to large nuclear reactors. While many studies have been performed on natural convection employing supercritical or subcritical fluids, little attention has been given to fluids in their transcritical regime. The latter has the potential to yield high performances while avoiding detrimental effects of two-phase systems (e.g. cavitation). In the present study, 2D …

Go With The Flow –Thermoelectric Energy, Shawn Bell

Middle School Lesson Plans

In this unit, students will learn how thermal energy be transferred and transformed. They will carry out investigations to gather evidence to support an explanation about direct conversion of heat into electrical energy. They will develop a model that shows the components of the system and changes in the system being investigated, and they will use evidence from the investigation to construct an explanation for how the energy flows.

Prosthetic Thermal Management Device, Garrett Dowd

Williams Honors College, Honors Research Projects

High temperatures in lower-limb prosthetics can lead to poor user skin conditions and mechanical slippage between the user’s limb and the prosthetic. This report presents an air-cooling device for a lower-limb prosthesis. This device’s purpose is to maintain a constant skin-prosthesis interface temperature. A compact heat sink and small fan were used to transfer the bio-heat to the ambient surroundings. By changing the power of the fan, the thermal resistance of the whole system can be adjusted to match various thermal loads and environmental temperatures. Heat pads were used to mimic the heat generation of a residual limb, and cooling …

A Numerical Study Of High Temperature And High Velocity Gaseous Hydrogen Flow In A Cooling Channel Of A Ntr Core, Sajan B. Singh

LSU New Orleans Theses and Dissertations

Two mathematical models (a one and a three-dimensional) were adopted to study, numerically, the thermal hydrodynamic behavior of flow inside a single cooling channel of a Nuclear Thermal Rocket (NTR) engine. The first model assumes the flow in the cooling channel to be one-dimensional, unsteady, compressible, turbulent, and subsonic. The working fluid (GH₂) is assumed to be compressible. The governing equations of the 1-D model are discretized using a second order accurate finite difference scheme. Also, a commercial CFD code is used to study the same problem. Numerical experiments, using both codes, simulated the flow and heat transfer …

Flame Temperature Imaging Of A Low Nox Burner Via Laser Rayleigh Scattering, Nicholas A. Smith

Master's Theses (2009 -)

Federal and global legislation are requiring increasingly stringent emission regulation on household appliances and in particular water heater burners. Emissions like NOx (NO and NO2) are a growing concern due to their adverse health effects and contribution to tropospheric ozone, acid rain, and smog formation. As NOx is more closely controlled, appliance manufacturers are developing low emission burners for use in water heaters.

Flame temperature is strongly correlated to NOx production. Hence, characterizing flame temperatures in new burners is a key part of improving upon burners used today and the development of future burners. Temperature measurements applied to a new, …

Barbeque Grill Temperature Distribution Design Improvement, Peter Gobell, Connor Mcgill, Thomas Willson

Mechanical Engineering

Team License to Grill set out to asses Bull Outdoor Products, Inc.’s barbeques and quantify the apparent uneven temperature distribution or “hot spots” and “cold spots” across the grill. This testing was accomplished with the design and fabrication of a test fixture allowing for accurate and repeatable temperature collection across the barbeque. With results that matched the sponsor’s claims of hot and cold spots, an engineering model was made using heat transfer and thermodynamic equations. Once the model somewhat resembled the experimental data, it was used to suggest different modifications that would allow for better temperature distribution. It was discovered …

Numerical Analysis Of The Thermodynamic Properties Of Various Gaseous Species, Addison Alexander

Lewis Honors College Capstone Collection

In the field of Fluid Mechanics, the determination of various thermodynamic properties of substances is of utmost importance. Many calculations require values for internal energy or specific heats. If experimental data does not exist to facilitate these calculations, an approximation must be made. This report analyzes three different approximation approaches to examine their relative strengths and weaknesses. The first approach, the Exact Method, uses NASA thermodynamic data to give a numerical interpolation. The second, the Summation Method, breaks up the total energy of the species into different contributions and performs an approximation based on thermodynamic theory. Finally, the Spectroscopic Method …

Irrigation Leak Detection: Using Flow Rate Sensors To Detect Breaks In An Irrigation System, Adam Openshaw, Kalvin Vu

Computer Engineering

This report details the exploration and invention of a mechanism that can detect breaks in an irrigation system. With the ultimate goal of conserving water, we have designed an inexpensive, self sustaining flow rate monitor that can be used to identify anomalies in an irrigation system and wirelessly communicate the status of the system to a base station. Our implementation can also determine the direction of the anomaly based on the nature of the anomaly itself. This means that multiple monitors can be used to pinpoint the location of a break within the system in addition to merely detecting its …

Effects Of Liquid Transpiration Cooling On Heat Transfer To The Diverging Region Of A Porous-Walled Nozzle, Daniel J. Schieb

Theses and Dissertations

This research effort investigated the effects of evaporation of water on the heat transferred to the wall of the diverging portion of a porous walled nozzle The AFIT High Pressure Shock Tube was used with a two-dimensional Mach 3 nozzle. One flat surface of the nozzle was fitted with a layer of porous stainless steel from the nozzle throat to the exit. This porous material was saturated with water to simulate liquid transpiration cooling. Surface temperature data was taken in this region using fast response coaxial thermocouple. Heat transfer was determined from the surface temperature history. Data was taken for …

Portable Electric Home Milk Pasteurizers, A. E. Baragar, P. A. Downs

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Two batch-type and one in-the-bottle type home milk pasteurizers were investigated to determine whether they comply with U.S. Public Health code temperature and time requirements for pasteurizers.