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Full-Text Articles in Engineering

Design And Analysis Of Compressed Air Power Harvesting Systems, Zachary James Sadler Dec 2017

Design And Analysis Of Compressed Air Power Harvesting Systems, Zachary James Sadler

Theses and Dissertations

Procedure for site discovery, system design, and optimization of power harvesting systems is developed with an emphasis on application to air compressors. Limitations for the usage of infrared pyrometers is evaluated. A system of governing equations for thermoelectric generators is developed. A solution method for solving the system of equations is created in order to predict power output from the device. Payback analysis is proposed for determining economic viability. A genetic algorithm is used to optimize the power harvesting system payback with changing quantities and varieties of thermoelectric generators, as well as the back work put into cooling the thermoelectric …


Design And Analysis Of Compressed Air Power Harvesting Systems, Zachary James Sadler Dec 2017

Design And Analysis Of Compressed Air Power Harvesting Systems, Zachary James Sadler

Theses and Dissertations

Procedure for site discovery, system design, and optimization of power harvesting systems is developed with an emphasis on application to air compressors. Limitations for the usage of infrared pyrometers is evaluated. A system of governing equations for thermoelectric generators is developed. A solution method for solving the system of equations is created in order to predict power output from the device. Payback analysis is proposed for determining economic viability. A genetic algorithm is used to optimize the power harvesting system payback with changing quantities and varieties of thermoelectric generators, as well as the back work put into cooling the thermoelectric …


Hydrodynamic And Thermal Effects Of Sub-Critical Heating On Superhydrophobic Surfaces And Microchannels, Adam M. Cowley Nov 2017

Hydrodynamic And Thermal Effects Of Sub-Critical Heating On Superhydrophobic Surfaces And Microchannels, Adam M. Cowley

Theses and Dissertations

This dissertation focuses on the effects of heating on superhydrophobic (SHPo) surfaces. The work is divided into two main categories: heat transfer without mass transfer and heat transfer in conjunction with mass transfer. Numerical methods are used to explore the prior while experimental methods are utilized for the latter. The numerical work explores convective heat transfer in SHPo parallel plate microchannels and is separated into two stand-alone chapters that have been published archivally. The first considers surfaces with a rib/cavity structure and the second considers surfaces patterned with a square lattice of square posts. Laminar, fully developed, steady flow with …


The Development And Numerical Modelling Of A Representative Elemental Volume For Packed Sand, Ashraf Thabet Sep 2017

The Development And Numerical Modelling Of A Representative Elemental Volume For Packed Sand, Ashraf Thabet

Electronic Thesis and Dissertation Repository

The motivation of this thesis is the development of simple microscopic-scale model (representative elemental volume; REV) that can be used to conduct flow and heat transfer simulations from which closure coefficients can be established for the volume-averaged transport equations for porous media (packed bed). The thesis provides a brief introduction to the computational technique adopted for the geometric generation of the REV (YADE), followed by a parametric study undertaken to reveal the minimum number of particles inside the REV that are required to mimic the appropriate physics. Additional analysis was conducted with the goal of determining the influence of deviation …


Thermal Measurement And Optimization Of Materials And Processes In A Li-Ion Cell, Vivek Vishwakarma Aug 2017

Thermal Measurement And Optimization Of Materials And Processes In A Li-Ion Cell, Vivek Vishwakarma

Mechanical and Aerospace Engineering Dissertations

Applications of Lithium-ion cells range from consumer electronics to electric cars because of their excellent electrochemical performance and energy density. However, a Li-ion cell also suffers from poor thermal transport characteristics, which reduces performance, causes overheating and thermal runaway. This work contributes towards thermal characterization of key Li-ion battery materials and identifies and improves the rate-limiting, material-level thermal conduction process in a Li-ion cell. Among the various materials within a Li-ion cell, the separator is expected to have the lowest thermal conductivity. In this work, we have carried out first-ever measurements of thermal conductivity and heat capacity of the separator …


Conjugate Heat Transfer And Thermo-Structural Analysis Of The Actively Cooled Multi-Stage Conical Nozzle And Hypersonic Low-Reynolds Diffuser Of The New Arc-Heated Wind Tunnel (Awht-Ii) Of The University Of Texas At Arlington, David Ray Campbell May 2017

Conjugate Heat Transfer And Thermo-Structural Analysis Of The Actively Cooled Multi-Stage Conical Nozzle And Hypersonic Low-Reynolds Diffuser Of The New Arc-Heated Wind Tunnel (Awht-Ii) Of The University Of Texas At Arlington, David Ray Campbell

Mechanical and Aerospace Engineering Theses

Arc-heated wind tunnels are the primary test facility for screening and qualification of candidate materials for hypersonic thermal protection systems (TPS). Via an electric arc that largely augments the enthalpy (by tens of MJ/kg) of the working fluid (Air, Nitrogen, CO2 in case of Mars-entry studies) passed through a converging-diverging nozzle at specific stagnation conditions, different regimes encountered in entry and re-entry hypersonic aerothermodynamics can be simulated. Because of the high-enthalpies (and associated temperatures that generally exceed the limits required by the thermo-structural integrity of the facility) the active cooling of the arc-heated wind tunnel’s parts exposed to the working …