Method For Determining Time-Resolved Heat Transfer Coefficient And Adiabatic Effectiveness Waveforms With Unsteady Film Cooling, James L. Rutledge, Jonathan F. Mccall

AFIT Patents

A new method for determining heat transfer coefficient (h) and adiabatic effectiveness (η) waveforms h(t) and η(t) from a single test uses a novel inverse heat transfer methodology to use surface temperature histories obtained using prior art approaches to approximate the h(t) and η(t) waveforms. The method best curve fits the data to a pair of truncated Fourier series.

Heating Element Including Carbon Nanotube (Cnt) Layer, Santhosh Kumar Loganathan, Virginie Rollin, Daewon Kim

Publications

Apparatus , materials , and techniques and techniques herein can include providing a deposited layer comprising a com posite material including carbon nanotubes ( CNTs ) . Accord ing to various examples , the composite can be applied to a substrate such as using a solution containing CNTs and other constituents such as sulfur . The solution can be spray applied to a substrate , or spin - coated upon a substrate , such as to provide a uniform , conductive , and optically - transpar ent film layer . In one application , such a film layer can be …

Modeling Of Methane Tank Depressurization In Cold Weather, Brittney Bridger-Burton, Kevin D. Cole

UCARE: Research Products

Non-metallic tanks are used in industry to store and transfer gasses such as methane. As the tanks are emptied, the properties of the gas change, causing heat transfer with the tank wall. When emptied while at low temperatures, liquid condensation can form and the tank lining can reach a critically low temperature, causing fracture to the tank wall. In this study, the emptying of methane in cold weather conditions from a non-metallic tank was modelled using Aspen Tech Software. A full tank of methane, at 250 bar and 288 K, was cooled to the following starting temperatures: 263, 253, 243, …

Oscillatory Flow Mechanism For Enhanced Heat Transfer, Sultan Taher Raml

Doctoral Dissertations and Master's Theses

This research project is about the use of an oscillatory flow mechanism to enhance heat transfer. The idea behind this is to induce oscillation of the end wall of one of two connected chambers of a heat exchanger which effectively will induce oscillation of the boundary layer within the connecting duct. The main idea of this thesis came from using species separation studies before 40 years ago in hyperventilation technology to help patients under anesthesia in hospitals. There are many applications for this research such as removing heat from chemical reactors, electrical devices and other enclosed environments such as submarines, …

Application Of A Multi-Zone Model For The Prediction Of Species Concentrations In Rapid Compression Machine Experiments, David Wilson

Master's Theses (2009 -)

Accurate chemical kinetic models, which predict species evolution and heat release rates in chemically reactive systems, are essential for further advancements in fuel and combustion technology. An experimental facility that is widely used for evaluating the accuracy of kinetic models is a rapid compression machine (RCM), which creates a well-defined reaction environment by compressing a reactive mixture inside a chamber. Generally, RCM experiments are conducted in order to obtain ignition delay data. However, chemical speciation data provides greater insight into reaction pathways, and is therefore a more rigorous benchmark for validating kinetic models. In order for a chemical kinetic model …

Notes On Contributions To The Science Of Rare Earth Element Enrichment In Coal And Coal Combustion Byproducts, James C. Hower, Evan J. Granite, David B. Mayfield, Ari S. Lewis, Robert B. Finkelman

Center for Applied Energy Research Faculty and Staff Publications

Coal and coal combustion byproducts can have significant concentrations of lanthanides (rare earth elements). Rare earths are vital in the production of modern electronics and optics, among other uses. Enrichment in coals may have been a function of a number of processes, with contributions from volcanic ash falls being among the most significant mechanisms. In this paper, we discuss some of the important coal-based deposits in China and the US and critique classification systems used to evaluate the relative value of the rare earth concentrations and the distribution of the elements within the coals and coal combustion byproducts.

Effect Of Spalled Particles Thermal Degradation On A Hypersonic Flow Field Environment, Raghava S. C. Davuluri, Huaibao Zhang, Alexandre Martin

Mechanical Engineering Faculty Publications

Two-way coupling is performed between a spallation code and a hypersonic aerothermodynamics CFD solver to evaluate the effect of spalled particles on the flow field. Time accurate solutions are computed in argon and air flow fields. A single particle simulations and multiple particles simulations are performed and studied. The results show that the carbon vapor released by spalled particles tend to change the composition of the flow field, particularly the upstream region of the shock.

Performance Evaluation Of Palm Oil-Based Biodiesel Combustion In An Oil Burner, Abdolsaeid Ganjehkaviri, Mohammad Nazri Mohd Jaafar, Seyed Ehsan Hosseini, Anas Basri Musthafa

Faculty Publications - Mechanical Engineering

This paper presents an experimental investigation of the combustion characteristics of palm methyl ester (PME), also known as palm oil-based biodiesel, in an oil burner system. The performance of conventional diesel fuel (CDF) and various percentages of diesel blended with palm oil-based biodiesel is also studied to evaluate their performance. The performance of the various fuels is evaluated based on the temperature profile of the combustor's wall and emissions, such as nitrogen oxides (NOx) and carbon monoxide (CO). The combustion experiments were conducted using three different oil burner nozzles (1.25, 1.50 and 1.75 USgal/h) under lean (equivalence ratio (φ) = …

Phase Change Materials-Assisted Heat Flux Reduction: Experiment And Numerical Analysis, Hussein J. Akeiber, Seyed Ehsan Hosseini, Mazlan A. Wahid, Hasanen M. Hussen, Abdulrahman Th Mohammad

Faculty Publications - Mechanical Engineering

Phase change materials (PCM) in the construction industry became attractive because of several interesting attributes, such as thermo-physical parameters, open air atmospheric condition usage, cost and the duty structure requirement. Thermal performance optimization of PCMs in terms of proficient storage of a large amount of heat or cold in a finite volume remains a challenging task. Implementation of PCMs in buildings to achieve thermal comfort for a specific climatic condition in Iraq is our main focus. From this standpoint, the present paper reports the experimental and numerical results on the lowering of heat flux inside a residential building using PCM, …

Experimental Study Of The Flow Of Ferrofluid In A Porous Media Under A Magnetic Field, Muskaan Khurana

Dissertations, Master's Theses and Master's Reports

This research presents results from a laboratory-scale experimental setup that was designed to visualize the behavior of ferrofluid percolation through a porous media. Ferrofluids are colloidal suspensions made of magnetic particles of a few nanometers and stabilized in carrier liquids like water or mineral oil. Ferrofluids get magnetized and align themselves in the direction of a magnetic field when a field gradient is applied.

With the help of this experiment we investigate the viability of controlling fluid flow in porous medium by a magnetic field in vicinity. The experiments show that ferrofluids can be used as a transporting media to …

Solar Thermal Collector, Hazel Tickner, Tyson Nakamura

All Undergraduate Projects

During the course of this project, a solar thermal collector and supporting stand were designed and manufactured to be used during Mechanical Engineering Technology labs. Students will be able to use the collector to heat water, with the sun being the only heat source. The collector was designed by calculating surface area limitations, estimated solar input, and desired efficiency, to find the required water flow rate. From there, the necessary pipe lengths and diameters were determined, and the solar thermal collector was constructed. Two pipe paths were manufactured: a curved path, and a manifold path. Students will be able to …

Oscillating Heat Pipe Performance With Evaporator Section Modifications, Mitchell Hoesing

Electronic Theses and Dissertations

The continuous development of electronic components to become faster and smaller has led to an increasing problem with thermal management. Thermal management ensures that the component operating temperatures are within a safe range, which maintains performance and improves reliability and lifespan. Traditional thermal management devices, such as the extruded-fin heat sink, are incapable of maintaining the safe operating temperature range for current and future high heat flux cooling applications. A device that has the capability to meet this growing need is the oscillating heat pipe. Oscillating heat pipes (OHPs) are passive, two-phase cooling devices that have been shown to transfer …

Shear Driven Suppressed Nucleation Annular Flow-Boiling In Millimeter-Scale Channels: Direct Numerical Simulations, Sharayu Bhasme

Dissertations, Master's Theses and Master's Reports

Many contemporary high heat-flux cooling applications are facilitated by mm-scale flow-boilers that operate in the steady annular suppressed nucleation regime (i.e., a thin evaporating liquid film flow covers the heated boiling-surface).

For such cases, this thesis presents a direct numerical simulation (DNS) approach. The steady algorithm and its accuracy are discussed. Representative detailed solutions for annular flow-boiling of FC-72 in a horizontal channel are presented.

An Experimental Investigation Of Heat Transfer For Arrays Of Impingement Jets Onto The Featured Surfaces With Cylindrical And Elliptical Raised Surfaces, Marc A. Medina

Honors Undergraduate Theses

This study focuses on multi-jet impingement for gas turbine geometries in which the objective is to understand the influence of the roughness elements on a target surface to the heat transfer. Current work has proven that implementing roughness elements for multi-jet impingement target surfaces has increased heat transfer ranging anywhere from 10-30%. This study has chosen to investigate three different roughness elements, elliptical in cross-section, to compare to smooth surface geometries for multi-jet impingement. An experimental was taken for this study to extend the current knowledge of multi-jet impingement geometries and to further understand the heat transfer performance. A temperature …

Energy Resources Use Metrics, Rahul Y. Nehete

Theses and Dissertations--Mechanical and Aerospace Engineering

Energy resources use has been considered as a key component of sustainable development. Data related to global, regional, state, sector, industry and process demonstrate that a significant reduction of energy resources for a given production rate in manufacturing processes requires an introduction of transformational technologies at the process level, propagating the impact to higher scales, leading not just to a gradual improvement of traditional technologies but to more sustainable development.

The study offers two approaches to the formulation of the limits of energy use in the context of sustainable development. The first is to construct a map of key selected …

Flow Visualization Of Buoyant Instability In A Cross-Flow: An Implication For Flame Spread Over Forest Fuel Beds, Nikolay Gustenyov

Theses and Dissertations--Mechanical and Aerospace Engineering

This thesis reports small-scale laboratory experiments designed to visualize the flow over a heated plate. A low-speed wind tunnel was built, and a heating plate was flush mounted on the wind tunnel floor to provide a uniform heat flux over its surface. A paper thin cloth soaked with commercially available Vaseline was placed on top of the heating plate to produce thick smoke streaks that were carried downstream by a horizontal airflow. Both LED light and a laser sheet of approximately 30-degrees open angle were separately used to illuminate this flow, the latter advanced downstream with 1-cm interval from the …

Kinetics Of Molten Metal Capillary Flow In Non-Reactive And Reactive Systems, Hai Fu

Theses and Dissertations--Mechanical and Aerospace Engineering

Wetting and spreading of liquid systems on solid substrates under transient conditions, driven by surface tension and viscous forces along with the interface interactions (e.g., a substrate dissolution or diffusion and/or chemical reaction) is a complex problem, still waiting to be fully understood. In this study we have performed an extensive experimental investigation of liquid aluminum alloy spreading over aluminum substrate along with corroboration with theoretical modeling, performed in separate but coordinate study. Wetting and spreading to be considered take place during a transient formation of the free liquid surface in both sessile drop and wedge-tee mating surfaces’ configurations. The …

Comparisons Of Ablator Experimental Performance To Response Modeling And Effects Of Water Phase Transition In Porous Tps Materials, David L. Smith

Theses and Dissertations--Mechanical and Aerospace Engineering

The Mars Science Laboratory Entry Descent and Landing Instrumentation (MEDLI) project performed extensive arc jet tests for development, qualification, and calibration of instrumented heat shield plugs. These plugs each contained several thermocouples for recording near-surface and in-depth temperature response of the Phenolic Impregnated Carbon Ablator (PICA) heat shield. The arc jet test results are entered into a comprehensive database so that broad trends across the test series can be compared. One method of analysis is to compare with ablator material response calculations and solve the in-depth heat conduction equations. Using the near-surface thermocouple measurements as a boundary condition in numerical …

Predictive Control Of Power Grid-Connected Energy Systems Based On Energy And Exergy Metrics, Meysam Razmara

Dissertations, Master's Theses and Master's Reports

Building and transportation sectors account for 41% and 27% of total energy consumption in the US, respectively. Designing smart controllers for Heating, Ventilation and Air-Conditioning (HVAC) systems and Internal Combustion Engines (ICEs) can play a key role in reducing energy consumption. Exergy or availability is based on the First and Second Laws of Thermodynamics and is a more precise metric to evaluate energy systems including HVAC and ICE systems. This dissertation centers on development of exergy models and design of model-based controllers based on exergy and energy metrics for grid-connected energy systems including HVAC and ICEs.

In this PhD dissertation, …

Experimental Investigation Of Fast Pyrolysis Of Arundo Donax In A Novel Paddle Reactor, Chintan Desai

Dissertations, Master's Theses and Master's Reports

The main objective of this research was to show the effectiveness of a novel paddle reactor for fast pyrolysis and study the effect of biomass particle size and reaction temperature of Arundo Donax a type of energy crop on the bio-oil yields. The novel paddle reactor showed effective mixing and heat transfer which were proved with the help of studying the residence time and the heating characteristics of the system respectively. The effect of different biomass particle sizes on the bio-oil yield was not significant, the bio-oil yield was approximately 50% for all the sizes. For Arundo Donax particle sizes …

Low Temperature Split Injection Spray Combustion: Ignition, Flame Stabilization And Soot Formation Characteristics In Diesel Engine Conditions, Ahmed Abdul Moiz

Dissertations, Master's Theses and Master's Reports

The aim of the PhD work is to investigate the fundamental differences in combustion behavior when split injections are used in low temperature combustion regime. In this thesis, the first injection is also called as pilot injection and second injection is also called as main injection. The broad aspects which are studied encompassing the investigation is to study the ignition delay, lift-off and soot formation of such a double split spray combustion. The mechanisms of ignition, lift-off and soot production are to be studied since the main ignition and lift-off were found to differ from the pilot which effect net …

Design Of Real-Time Combustion Feedback System And Experimental Study Of An Rcci Engine For Control, Jayant Kumar Arora

Dissertations, Master's Theses and Master's Reports

Premixed compression ignition (PCI) technologies offer high efficiency and low emissions but are usually confined by limited operation range as well as high pressure rise and heat release rate. In this work, a more recently developed PCI mode is explored where in-cylinder blending of two fuels with different auto-ignition characteristics (diesel and gasoline) is utilized to create reactivity stratification such that heat release rate and combustion timing can be controlled. This mode has been defined as Reactivity Controlled Compression Ignition (RCCI).

As part of this thesis, the main aim is to study various parameters that can be used to control …

An Experimental Investigation Of The Effect Of Temperature And Space Velocity On The Performance Of A Cu-Zeolite Flow-Through Scr And A Scr Catalyst On A Dpf With And Without Pm Loading, Vaibhav Kadam

Dissertations, Master's Theses and Master's Reports

Abstract The heavy-duty diesel (HDD) engines use the diesel oxidation catalyst (DOC), catalyzed particulate filter (CPF) and urea injection based selective catalytic reduction (SCR) systems in sequential combination, to meet the US EPA 2010 PM and NOₓ emission standards. The SCR along with a NH₃ slip control catalyst (AMOX) offer NOₓ reduction >90 % with NH₃ slipHowever, there is a strong desire to further improve the NOₓ reduction performance of such systems, to meet the California Optional Low NOₓ Standard implemented since 2015. Integrating SCR functionality into a diesel particulate filter (DPF), by coating the SCR catalyst on the DPF, …

Economical Retrofit System To Reduce Cooking Emissions In Third World Dwellings, Jonathan Vanzummeren, Tyler Sturgeon, Ben Dalessandro

Williams Honors College, Honors Research Projects

Abstract:

The purpose of this document is to propose and demonstrate the feasibility and effectiveness of substituting an open flame biomass cooking process with a closed system with the capabilities of sustaining an adequate fire. Clay ovens or “chulhas” are the traditional piece of cooking equipment used in poorer areas of the world. They are often built inside cramped one-room housing units with little or no ventilation. The emissions released from burning fuel sources such as wood, coal, or animal waste bring with them detrimental and often fatal health problems and results in approximately 1.3 million deaths per year.

The …

Experimental Study, Modelling And Controller Design For An Rcci Engine, Naga Nithin Teja Kondipati

Dissertations, Master's Theses and Master's Reports

Low Temperature Combustion (LTC) has got widespread attention over the past two decades in the field of Automotive Research and Development due to it’s potential for achieving higher efficiencies with near-zero engine out NOx and soot emissions. Among all the LTC strategies Reactivity controlled compression ignition (RCCI) has shown the most promising results due to it’s precise control over combustion phasing and heat release rate. However, RCCI being a dual-fuel stratified combustion, precise control over the injection timing of direct injected fuel and in-cylinder fuel reactivity of the mixture needs to be controlled effectively in order to achieve gross indicated …

Competition Vehicle Based Intake Manifold Design, Joshua N. Matiash

Dissertations, Master's Theses and Master's Reports

A competitive vehicle in Formula SAE needs to be easy for unskilled drivers to extract the maximum performance from. This requires a predictable and manageable torque curve. This report details the development of an intake manifold for a Formula SAE car from a vehicle-based approach to produce this manageable and predictable torque. The current vehicle was instrumented and driven on a representative track to determine the usage of available torque. Based on these findings an ideal torque curve was chosen that favored increased torque at upper engine speed ranges and decreased torque at lower engine speed ranges. A 1-D engine …

An Assessment Of The Validity Of The Kinetic Model For Liquid-Vapor Phase Change By Examining Cryogenic Propellants, Kishan Bellur

Dissertations, Master's Theses and Master's Reports

Evaporation is ubiquitous in nature and occurs even in a microgravity space envi- ronment. Long term space missions require storage of cryogenic propellents and an accurate prediction of phase change rates. Kinetic theory has been used to model and predict evaporation rates for over a century but the reported values of accommodation coefficients are highly inconsistent and no accurate data is available for cryogens. The proposed study involves a combined experimental and computational approach to ex- tract the accommodation coefficients. Neutron imaging is used as the visualization technique due to the difference in attenuation between the cryogen and the metallic …