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Heat Transfer, Combustion Commons™

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2010

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Articles 1 - 11 of 11

Full-Text Articles in Heat Transfer, Combustion

Modeling And Numerical Investigation Of Hot Gas Defrost On A Finned Tube Evaporator Using Computational Fluid Dynamics, Oai The Ha Nov 2010

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 …


Irrigation Leak Detection: Using Flow Rate Sensors To Detect Breaks In An Irrigation System, Adam Openshaw, Kalvin Vu Jun 2010

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 …


Pg&E Flow Loop Simulator, Cole Brooks, Seth Berger, Ben Thacker Jun 2010

Pg&E Flow Loop Simulator, Cole Brooks, Seth Berger, Ben Thacker

Mechanical Engineering

PG&E’s Diablo Canyon Power Plant requested a full-sized Flow Loop Simulator to train technicians by giving them hands-on experience. The basic design requirements were established to determine the scope of the project and develop the specific characteristics of the system. The detailed system design is composed of a piping schematic, a three-dimensional layout of the system components and piping, and a skid structure for the support and transportation of the system. Heat transfer and fluid mechanics were used to analyze the system to size components.


Design And Analysis Of A Low Temperature Co-Fired Ceramic Micro Combustor, Matthew H. Mccrink May 2010

Design And Analysis Of A Low Temperature Co-Fired Ceramic Micro Combustor, Matthew H. Mccrink

Boise State University Theses and Dissertations

This thesis details the design and construction of a Low Temperature Co-Fired Ceramic (LTCC) micro combustion system. The design of the combustor requires a detailed analysis of the flame’s operational properties and stability. To this end, an analytic model was created to address these concerns. These results were used in conjunction with a detailed numerical analysis to determine the stable operating range of the combustors. The combustion of gaseous fuels requires a device with a lower bound on the channel feature size. This lower limit for combustion corresponds to the minimum quenching distance of the specific fuel being used and …


Development Of Hydrogen Direct Injection For Conversion Of Internal Combustion Engines, Maxwell A. Wilson May 2010

Development Of Hydrogen Direct Injection For Conversion Of Internal Combustion Engines, Maxwell A. Wilson

UNLV Theses, Dissertations, Professional Papers, and Capstones

The trend toward usage of vehicles that operate on alternative, renewable forms of energy storage has generated areas for development of new products that will facilitate implementation of new automotive fuel systems. As the reality of a hydrogen-fueled economy emerges, intermediate technologies may be necessary for the transition between hydrocarbon fueled internal combustion engines and hydrogen powered fuel cells. The University of Nevada Las Vegas Center for Energy Research has developed a method for converting the common hydrocarbon fueled internal combustion engine to hydrogen direct injected fueling. This thesis describes the second phase of development and involves the design, fabrication …


Numerical Investigation Of Pre-Detonator Geometries For Pde Applications, Robert T. Fievisohn Mar 2010

Numerical Investigation Of Pre-Detonator Geometries For Pde Applications, Robert T. Fievisohn

Theses and Dissertations

A parametric study was performed to determine optimal geometries to allow the successful transition of a detonation from a pre-detonator into the thrust tube of a pulse detonation engine. The study was performed using a two-dimensional Euler solver with progress variables to model the chemistry. The geometrical configurations for the simulations look at the effect of shock reflections, flow obstructions, and detonation diffraction to determine successful geometries. It was observed that there are success and failure rates associated with pre-detonators. These success rates appear to be determined by the transverse wave structure of a stably propagating detonation wave and must …


Investigation Of Thermal Management And Metamaterials, Calvin T. Roman Mar 2010

Investigation Of Thermal Management And Metamaterials, Calvin T. Roman

Theses and Dissertations

Thermal metamaterials are materials composed of engineered, microscopic structures that exhibit unique thermal performance characteristics based primarily on their physical structures and patterning, rather than just their chemical composition or bulk material properties. The heat transfer performance attributes of a thermal metamaterial are such that similar performance cannot be obtained using conventional materials or compounds. Thermal metamaterials are an emerging technology, and are just now beginning to be acknowledged and developed by the microelectronics and material sciences community. This thesis effort analyzed the current state of thermal metamaterial research, examined the physics and theory of heat transfer and electrical conductivity …


Adhesion At Diamond /Metal Interfaces: A Density Functional Theory Study, Haibo Guo, Yue Qi, Xiaodong Li Feb 2010

Adhesion At Diamond /Metal Interfaces: A Density Functional Theory Study, Haibo Guo, Yue Qi, Xiaodong Li

Faculty Publications

To understand the basic material properties required in selecting a metallic interlayer for enhanced adhesion of diamondcoatings on the substrates, the interfaces between diamond and metals with different carbide formation enthalpies (Cu, Ti, and Al) are studied using density functional theory. It is found that the work of separation decreases, while the interface energy increases, with the carbide formation enthalpy ΔHf (Tiys (Ti>Cu>Al), is needed to achieve a higher overall interface strength. In addition, when the surface energy is larger than the interface energy, a wetted diamond/metal interface is formed during diamondnucleation, providing the strongest adhesion …


Integrated Vehicle Thermal Management For Advanced Vehicle Propulsion Technologies: Preprint., K. Bennion, M. Thornton Feb 2010

Integrated Vehicle Thermal Management For Advanced Vehicle Propulsion Technologies: Preprint., K. Bennion, M. Thornton

Publications (T)

A critical element to the success of new propulsion technologies that enable reductions in fuel use is the integration of component thermal management technologies within a viable vehicle package. Vehicle operation requires vehicle thermal management systems capable of balancing the needs of multiple vehicle systems that may require heat for operation, require cooling to reject heat, or require operation within specified temperature ranges. As vehicle propulsion transitions away from a single form of vehicle propulsion based solely on conventional internal combustion engines (ICEs) toward a wider array of choices including more electrically dominant systems such as plug-in hybrid electric vehicles …


Simulation Algorithm And Validation Of A Photovoltaic Water Pumping System, I. Odeh, Y. Yohannis, Brian Norton Jan 2010

Simulation Algorithm And Validation Of A Photovoltaic Water Pumping System, I. Odeh, Y. Yohannis, Brian Norton

Articles

A photovoltaic (PV) water pumping system has been modelled using TRNSYS considering a power supply, a direct current (DC)/alternating current (AC) inverter, an AC induction motor, a centrifugal pump, a well, a water storage tank, and an overflow protection device. The model emulates actual pumping head curves, uses numerical methods to determine pump system working points, and includes a storage tank as a component in the system. It simulates PV-powered water pumping systems, constant voltage tracking, voltage frequency modulation, and maximum power point tracking algorithms; variable inverter frequency with variable motor efficiency, variable inverter frequency with constant motor efficiency, and …


Nonequilibrium Thermodynamics Modeling Of Coupled Biochemical Cycles In Living Cells, Yaşar Demirel Jan 2010

Nonequilibrium Thermodynamics Modeling Of Coupled Biochemical Cycles In Living Cells, Yaşar Demirel

Yaşar Demirel Publications

Living cells represent open, nonequilibrium, self organizing, and dissipative systems maintained with the continuous supply of outside and inside material, energy, and information flows. The energy in the form of adenosine triphosphate is utilized in biochemical cycles, transport processes, protein synthesis, reproduction, and performing other biological work. The processes in molecular and cellular biological systems are stochastic in nature with varying spatial and time scales, and bounded with conservation laws, kinetic laws, and thermodynamic constraints, which should be taken into account by any approach for modeling biological systems. In component biology, this review focuses on the modeling of enzyme kinetics …