Energy Systems Commons^™

Advanced Visualization Techniques Of Hot-Jet Combustion Of Lean And Ultra-Lean Substances, Timothy I. Machin, Li Qiao

The Summer Undergraduate Research Fellowship (SURF) Symposium

Research has been conducted on ignition of natural gas as a potential replacement for fossil fuels. A reason natural gas is not widely used and adapted is because of the harmful emissions created when combusted in rich mixtures, but if the gas can be burned at a lean or ultra-lean equivalence ratio, these emissions can be reduced or even eliminated. One method of burning lean and ultra-lean substances is by use of hot-jet ignition. This method ignites the substance near its combustion temperature, reducing the harmful emissions. This method is not yet fully understood, and so research must be done …

Experimental Study Of Co2 Recycling Using Metal-Oxide Enhanced Coconut Char Gasification: Catalytic Effect Of Potassium Carbonate On Gasification, Mengqi Gao, Indraneel Sircar, Jay P. Gore

The Summer Undergraduate Research Fellowship (SURF) Symposium

Biomass gasification is an important process in the production of bio-derived fuels and renewable energy. Biomass gasification with CO₂ is an endothermic process requiring high temperatures, resulting in low process-efficiency. Metals found in the ash in biomass feedstock have shown rate-promoting effects on the C-CO₂ reaction and have motivated the study of low-temperature catalytic gasification. The present study investigates the catalytic effects of potassium (K) on the biomass gasification reactivity of a coconut-derived char (>99.9% carbon) within the temperature range of 600 – 1000 ^oC. A wet-impregnation technique is used to prepare K-treated chars. Gasification of …

An Applied Numerical Simulation Of Entrained-Flow Coal Gasification With Improved Sub-Models, Xijia Lu

LSU New Orleans Theses and Dissertations

The United States holds the world's largest estimated reserves of coal and is also a net exporter of it. Coal gasification provides a cleaner way to utilize coal than directly burning it. Gasification is an incomplete oxidation process that converts various carbon-based feedstocks into clean synthetic gas (syngas), which can be used to produce electricity and mechanical power with significantly reduced emissions. Syngas can also be used as feedstock for making chemicals and various materials.

A Computational Fluid Dynamics (CFD) scheme has been used to simulate the gasification process for many years. However, many sub-models still need to be developed …

Numerical Modeling Of Heat Pipe Radiator And Fin Size Optimization For Low And No Gravity Environments, Virginia Ruth Bieger

UNLV Theses, Dissertations, Professional Papers, and Capstones

A heat-pipe radiator element has been designed and modeled to study the efficiency of heat transfer for low and no gravity environments, like in lunar environments. The advantages of using heat pipe includes the significant weight reducing and heat transfer efficiency. The heat transfer can be enhanced by the use of condenser sections with attached fins.

A series of various geometries of solid fins and heat pipes with and without fins were modeled using FLUENT®. This was done to determine the validity of using a heat pipe in lieu of a solid fin projection. A heat pipe had a 25 …

Lunalight - Bringing Light To The Expanding World, Gabriela M. Igel, Daniel J. Patrick, Kimberley M. Smith

Materials Engineering

The LunaLight, a solar rechargeable light and cell phone charger, addresses the lack of access to electricity faced by 1.4 billion of the world’s population (International Finance Corporation). The LunaTech team has developed a product that is bright, simple, compact, versatile and competitive with existing products. Through a partnership with the non-profit organization One Million Lights, LunaTech has improved a previous team’s design to address user feedback, concerns of durability, and manufacturability.

The LunaLight design includes a 5 component plastic housing held together by 4 screws, a surface mounted PCB, a lithium-ion (Li-Ion) battery, one high-brightness LED, a solar panel, …

High Temperature Filter Test Unit Upgrades, Blair Frandeen, Will Schill, Erick Shewmaker, Joshua Turgeon

Mechanical Engineering

The purpose of this project was to improve the existing High Temperature Filter Test Unit (HTTU) by optimizing performance and adding new features. These features include viewing ports and a camera system for observation of tests, a leak detection system, and a flame impingement system. Additional considerations included improving the current operation of the HTTU by reducing test time and energy loss. The HTTU is designed to test High Efficiency Particulate Air (HEPA) filters at temperatures up to 1300 ˚F, creating conditions which simulate a fire in a chemical processing facility. The HTTU was originally built as a Cal Poly …

Transient And Quasi-Steady Thermal Behaviour Of A Building Envelope Due To Retrofitted Cavity Wall And Ceiling Insulation, Aimee Byrne, Gerard Byrne, Anna Davies, Anthony Robinson

Articles

Accurate understanding of the thermal behaviour of building components is essential for predicting heat-ing or cooling needs and facilitates the implementation of more successful energy saving strategies and retrofits. This paper focuses on a specific measure commonly introduced through the residential energy efficiency retrofit programmes in Ireland–insulation. Traditionally, assessments of the performance of building envelopes have been based on assumed thermal resistances of the materials involved, labora-tory tests and computer modelling. The aim of the present work is to investigate the in situ thermal behaviour of a case study building and its components under transient and quasi-steady environmental conditions, comparing …

Cerium Oxide (Ceo2) Promoted Oxygen Carrier Development And Scale Modeling Study For Chemical Looping Combustion, Fang Liu

Theses and Dissertations--Mechanical and Aerospace Engineering

According to IPCC reports, the greenhouse gas CO₂ is responsible for global climate change. Studies show that CO₂ concentration reached a level of 400 ppm in 2013, or 40 % above pre-industrial levels. The contribution of CO₂ from industrial activity to increasing global CO₂ concentrations is widely accepted and points to the need to reduce the emission of this greenhouse gas.One possible combustion technology that shows promise for reducing CO₂ emissions is chemical looping combustion (CLC). It is an oxy-fuel technology, but has the advantages of in situ oxygen separation, low NO_x emissions and …

Latent Heat Thermal Energy Storage With Embedded Heat Pipes For Concentrating Solar Power Applications, Christopher Robak

Master's Theses

An innovative, novel concept of combining heat pipes with latent heat thermal energy storage (LHTES) for concentrating solar power (CSP) applications is explored. The low thermal conductivity of phase change materials (PCMs) used in LHTES presents a design challenge due to slow heat transfer rates during heating and cooling of the material. Heat pipes act to decrease the thermal resistance in the PCM, increasing the overall heat transfer rate sufficiently for use in CSP. First, a laboratory scale experiment is presented to validate the concept of using heat pipes in LHTES to reduce thermal resistance in PCM. A commercial scale …

Computational Models Of Sub-Divided Thermal Energy Storage Tanks Used In Concentrating Solar Power Plants With Parabolic Trough Collectors, Jesus D. Ortega ^, Vinod Kumar *

COURI Symposium Abstracts, Spring 2012

No abstract provided.

Numerical Simulation Of Natural Convection In Rectangular Enclosures Of Varying Aspect Ratios And Its Feasibility In Environmental Impact Management Studies, Charles R. Walker

College of Graduate Studies: Theses & Dissertations

Author's abstract: Numerical simulation was used to investigate natural convection in horizontal and vertical enclosures with and without an internal heat source. Natural convection in rectangular enclosures is found in many real-world applications. Included in these applications are the energy efficient design of buildings, operation and safety of nuclear reactors, solar collector design, passive energy storage, heat transfer across multi-pane windows, thermo-electric refrigeration and heating devices, and the design-for-mitigation of optical distortion in large-scale laser systems. Considering all these applications, especially controlling heat transfer in nuclear power plants, knowledge and research results of natural convection in enclosure play a vital …

Analysis Of Biomass/Coal Co-Gasification For Integrated Gasification Combined Cycle (Igcc) Systems With Carbon Capture, Henry A. Long Iii

LSU New Orleans Theses and Dissertations

In recent years, Integrated Gasification Combined Cycle Technology (IGCC) has become more common in clean coal power operations with carbon capture and sequestration (CCS). Great efforts have been spent on investigating ways to improve the efficiency, reduce costs, and further reduce greenhouse gas emissions. This study focuses on investigating two approaches to achieve these goals. First, replace the subcritical Rankine steam cycle with a supercritical steam cycle. Second, add different amounts of biomass as feedstock to reduce emissions. Finally, implement several types of CCS, including sweet- and sour-shift pre-combustion and post-combustion.

Using the software, Thermoflow®, this study shows that utilizing …

Experimental And Numerical Investigations Of Tubular-Shaped Direct Methanol Fuel Cells (Dmfcs), Travis R. Ward

Master's Theses

This study focuses on both the numerical and experimental investigations of the novel, passively operated, tubular-shaped, Direct Methanol Fuel Cell (DMFC) as an alternative geometry to the traditional planar-shaped fuel cell. The benefit of the tubular geometry compared to the planar geometry is the higher instantaneous volumetric power density provided by the larger active area, which could be beneficial in applications that require a high instantaneous power while occupying a small volume. First, a two-dimensional, two-phase, non-isothermal model was developed to investigate the steady-state performance and design characteristics of a tubular-shaped, passive DMFC. It was found that a higher ambient …

Characteristics Of The Hydrogen Electrode In High Temperature Steam Electrolysis Process, Chao Jin, Chenghao Yang, Fanglin Chen

Faculty Publications

YSZ-electrolyte supported solid oxide electrolyzer cells (SOECs) using LSM-YSZ oxygen electrode but with three types of hydrogen electrode, Ni–SDC, Ni–YSZ and LSCM–YSZ have been fabricated and characterized under different steam contents in the feeding gas at 850°C. Electrochemical impedance spectra results show that cell resistances increase with the increase in steam concentrations under both open circuit voltage and electrolysis conditions, suggesting that electrolysis reaction becomes more difficult in high steam content. Pt reference electrode was applied to evaluate the contributions of the hydrogen electrode and oxygen electrode in the electrolysis process. Electrochemical impedance spectra and over potential of both electrodes …

Analyse Du Comportement Réel Et De L'Optimisation Structurelle Des Cycles De Turbines À Gaz, Alexandru Dobrovicescu, Michel Feidt, Lavinia Grosu, Jim Mcgovern, Georgiana Tirca-Dragomirescu

Conference Papers

L’article présente une étude comparative, basée sur l’analyse exégétique, de l’effet de non prise en considération du comportement réel de l’agent thermique et de l’utilisation des modèles simplifiés pour calculer les performances des cycles de turbines à gaz avec et sans récupération de chaleur. Un intérêt spécial a été réservé au processus de combustion et au transfert de chaleur dans le préchauffeur d’air. La variation des destructions et des pertes d’exergie par rapport à la variation des paramètres fonctionnels est présentée.

Modeling And Numerical Investigation Of Hot Gas Defrost On A Finned Tube Evaporator Using Computational Fluid Dynamics, Oai The Ha

Master's Theses

Defrosting in the refrigeration industry is used to remove the frost layer accumulated on the evaporators after a period of running time. It is one way to improve the energy efficiency of refrigeration systems. There are many studies about the defrosting process but none of them use computational fluid dynamics (CFD) simulation. The purpose of this thesis is (1) to develop a defrost model using the commercial CFD solver FLUENT to simulate numerically the melting of frost coupled with the heat and mass transfer taking place during defrosting, and (2) to investigate the thermal response of the evaporator and the …

Rayleigh Flow Of Two-Phase Nitrous Oxide As A Hybrid Rocket Nozzle Coolant, Lauren May Nelson

Master's Theses

The Mechanical Engineering Department at California Polytechnic State University in San Luis Obispo currently maintains a lab-scale hybrid rocket motor for which nitrous oxide is utilized as the oxidizer in the combustion system. Because of its availability, the same two-phase (gas and liquid) nitrous oxide that is used in the combustion system is also routed around the throat of the hybrid rocket’s converging-diverging nozzle as a coolant. While this coolant system has proven effective empirically in previous tests, the physics behind the flow of the two-phase mixture is largely unexplained. This thesis provides a method for predicting some of its …

Heat Transfer Correlations For Low Approach Evaporative Cooling Systems In Buildings, Ben Costelloe, Donal Finn

Articles

The experimental performance of an open industrial scale cooling tower, utilising small approach temperature differences (1–3 K), for rejection of heat at the low water temperatures (11–20 °C) typical of chilled ceilings and other sensible air–water heat dissipation systems in buildings, is examined. The study was carried out under temperate maritime climatic conditions (3–18 °C wet-bulb temperature range). Initially a theoretical analysis of the process at typical conditions for this climate was conducted, which indicated that a water to air (L/G) mass flow rate ratio of less than 1.0 was required for effective operation. Consequently for these low L/G ratios, …

Knowledge-Based Information Resource Management System For Materials Of Sodium-Cooled Fast Reactor, Sean Hsieh

Reactor Campaign (TRP)

In the development of advanced fast reactors, materials and coolant/material interactions pose a critical barrier for higher temperature and longer core life designs. For advanced burner reactors (sodium cooled) such as EBR-II and FFTF, experience has shown that the qualified structural materials and fuel cladding severely limits the economic performance. In other liquid metal cooled reactor concepts, advanced materials and better understanding and control of coolant and materials interactions are necessary for realizing the potentials.

Liquid sodium has been selected as the primary coolant candidate for Gen. IV nuclear energy systems. Global Nuclear Partnership (GNEP) Advanced Burned Reactor (ABR) has …

Modeling And Design Algorithms For Electromagnetic Pumps, Daniel P. Cook, Yitung Chen, Jian Ma

Reactor Campaign (TRP)

Electromagnetic (EM) induction pumps are used extensively in current and proposed nuclear power systems and industrial molten metal transfer operations. Although the Magnetohydrodynamic (MHD) theory that underlies the operation of these types of pumps has been studied extensively in the past few decades, the design of specific EM pumping systems for specific flow cases requires computational tools and expertise, which is lacking in the U.S. However, for the past two years, researchers at UNLV have been utilizing the TC-1 liquid metal loop system at UNLV and an Annular Linear Induction Pump (ALIP) to drive the liquid metal and to develop …

Thermal Transient Flow Rate Sensor For High Temperature Liquid Metal Cooled Nuclear Reactor, Yingtao Jiang, Jian Ma

Reactor Campaign (TRP)

In nuclear power plants and accelerator driven systems (ADS) for nuclear waste treatment, it is important to monitor the coolant flow rate in the reactor core and pipe-line. In such a strong irradiation, high pressure, and temperature environment, the existing flow measurement techniques (such as Electromagnetic flow meters, Ultrasonic flow meters, Turbine flow meters, etc.) are not accurate and reliable.

The measurement of flow rates (mass flow rates or volume flow rate) plays a notable role in monitoring and controlling the experimental conditions. The bulk flow rates can be obtained through direct methods, which measure the amount of discharged fluids …

Knowledge-Based Information Resource Management System For Materials Of Sodium-Cooled Fast Reactor, Sean Hsieh

Reactor Campaign (TRP)

In the development of advanced fast reactors, materials and coolant/ material interactions pose a critical barrier for higher temperature and longer core life designs. For sodium-cooled fast reactors (SFRs) such as the Experimental Breeder Reactors in Idaho and the Fast Flux Test Facility in Hanford, experience has shown that qualified structural materials and fuel cladding severely limits their economic performance.

Liquid sodium has been selected as the primary coolant candidate for the Advanced Burner Reactor (ABR) of the Global Nuclear Partnership (GNEP). Materials improvement has been identified as a major thrust to improve fast reactor economics. Researchers from universities, national …

Modeling And Design Algorithms For Electromagnetic Pumps, Daniel P. Cook

Reactor Campaign (TRP)

Electromagnetic (EM) induction pumps are used in a number of nuclear energy related applications, such as circulation of molten lead-bismuth eutectic alloys in neutron targets, and circulation of liquid sodium metal in Gen IV Sodium-cooled Fast Reactors (SFR). Because EM pumps have no moving parts which can fail, they are considerably more reliable than conventional mechanical pumps for molten metal usage, and thus EM pumps are favored over mechanical pumps even though their pumping efficiency is lower and their initial cost is higher when compared to mechanical pumps of similar flow rates.

The research objectives of this task are:

• A …

Thermal Transient Flow Rate Sensor For High Temperature Liquid Metal Cooled Nuclear Reactor, Yingtao Jiang

Reactor Campaign (TRP)

In nuclear power plants and accelerator driven system (ADS) for nuclear waste treatment, it is important to monitor the coolant flow rate in the reactor core and pipe-line. In such a strong irradiation, high pressure and temperature environment, no accurate local flow measurement technique is readily available. Electromagnetic (EM) flow meter is popular in low temperature application as it is a non-intrusive technology. However, additional voltage will be produced due to temperature, flow, pressure, the chemical properties of the liquid metal and surface condition of the steel walls. In addition, the non-definite wetting behavior of liquid lead-bismuth to the electrically …

Magnetohydrodynamic Simulation Of Electromagnetic Pump In Tc-1, Lillian J. Ratliff

Reactor Campaign (TRP)

The pilot molten lead-bismuth target circuit (TC-1) in university of Nevada Las Vegas (UNLV) was designed for beam power of 1 MW accelerator driven system (ADS). The TC-1 is a liquid lead-bismuth eutectic (LBE) circulation loop. Circulation of the liquid alloy is driven by an annular linear induction pump (ALIP). Experimental measurements of system parameters have yielded a surprisingly low pump efficiency of less than 1%. A numerical study of the pump efficiency is being conducted to determine which operational parameters are responsible for this low efficiency and to give insight into future EM pump design. The numerical study will …

Quantifying Savings From Improved Boiler Operation, Kevin Carpenter, J. Kelly Kissock

Mechanical and Aerospace Engineering Faculty Publications

On/off operation and excess combustion air reduce boiler energy efficiency. This paper presents methods to quantify energy savings from switching to modulation control mode and reducing excess air in natural gas fired boilers.

The methods include calculation of combustion temperature, calculation of the relationship between internal convection coefficient and gas flow rate, and calculation of overall heat transfer assuming a parallel-flow heat exchanger model. The method for estimating savings from changing from on/off to modulation control accounts for purge and drift losses through the boiler and the improved heat transfer within the boiler due to the reduced combustion gas flow …

Coupled Thermal Fluid Modelling Of A Low Embedded Energy Solar Thermal Collector, Myrrha Corcoran

Theses

Flat-plate collectors are the most economical and are popular in solar domestic heating water system since they are usually permanently fixed in position, have simple construction, and require little maintenance. The design of a solar energy system is generally concerned with obtaining maximum efficiency at minimum cost. The aim of this thesis was to develop a mathematical model, for a forced convection solar heated water system. The solar collector in this study incorporated a honeycombed extruded polycarbonate structure, for both the cover and water channels.

A very detailed thermal analysis of the flat-plate solar collector was carried out to predict …

Mechanics Of Composite Materials In Fuel Cell Systems, Kenneth Reifsnider, Xinyu Huang, G. Ju, Matthew Feshler, K. An

Faculty Publications

The science and technology that are fundamental to the concept of composite materials are also the foundation for the construction and function of fuel cells and fuel cell systems. The present paper outlines this relationship in the context of the physics and chemistry that are enabled by the specific selection and arrangement of constituents of the “functional composite” fuel cell. General principles of operation are described, and fundamental issues are defined that must be addressed by the composites community if the fuel cell science and engineering is to advance. Examples of several types of functional composite fuel cells are presented, …

Optimisation Of Heat Transfer And Fluid Flow In The Cooling Of Building Integrated Photovoltaic Facades., Eoin Patrick Hodge

Theses

The aim of this research was to explore the effects of mature and developing technologies from aeronautical industries such as impingement and film cooling, and electronic cooling techniques, in the setting up of different laminar and turbulent flow regimes on PV cooling duct heat transfer rates, with air flow as that brought about with natural buoyancy effects in a vertical building facade. The problem of efficiency losses in PV panels, due to overheating, is one of the factors restricting the development and use of this renewable power source. PV panels can experience very high temperatures, due to the heat input …

Entropy Generation In A Rectangular Packed Duct With Wall Heat Flux, Yaşar Demirel, Ramazan Kahraman

Papers in Thermal Mechanics

The entropy generation due to heat transfer and friction has been calculated for fully developed, forced convection flow in a large rectangular duct, packed with spherical particles, with constant heat fluxes applied to both the top (heated) and bottom (cooled) wall. An approximate analytical expression for the velocity profile developed for packed bed with H/dp > 5 has been used together with the energy equation of fully developed flow to calculate the non isothermal temperature profiles along the flow passage. The velocity profile takes into account the increase in the velocity near the wall due to the higher voidage in this …