Development of variable speed horizontal axis wind turbines has resulted in a need for an analysis code with a rotor speed degree-of-freedom. This study develops a five degree-of-freedom time domain computer code that evaluates blade and rotor, mean and cyclic loads with nonlinear aerodynamics together with atmospheric turbulence as a...
Predicting condensation flow regimes and the associated heat transfer and pressure drop in microchannels is critical for designing terrestrial and space systems for heating, cooling, power generation, and advanced manufacturing. It is well established that in flows approaching the microscale (Dh < 1 mm) gravity-dominated flow regimes become less relevant,...
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Brian M. Fronk
Predicting condensation flow regimes and the associated heat transfer
Nucleation and growth kinetics of oxygen precipitates and bulk
defects in epitaxial silicon wafers were investigated. Low temperature
nucleation heat treatments were applied to the well characterized
epitaxial silicon wafers before and after the epitaxial deposition
processing. Subsequently the wafers were heat treated at a high
temperature.
In the case...
This work investigates the in-tube condensation of low global warming potential (GWP) zeotropic refrigerant mixtures R448A, R450A, R452A, R454B and R454C. These refrigerants have been proposed for a wide range of commercial heating, ventilation, air-conditioning applications, but their heat and momentum transport phenomenon were not well understood. Thus, in this...
This work compares the condensation heat transfer and pressure drop for zeotropic refrigerant R-454C and its individual components, R-32 and R-1234yf, in horizontal microfin tubes. One microfin tube has a 4 mm outer diameter, 0.18 mm wall thickness, and a surface area ratio of 1.56. The second tube has a...
This thesis reports on an investigation of flow patterns in
shallow geothermal wells in Klamath Falls, Oregon, Although
wells have been extensively used in the area, the exact nature of
the flows in the wells has not been characterized.
Flow characterization is a principal object of this study.
Horizontal crossflows...
In this thesis the critical parameters involved in the
dislodgement and deformation of microbubbles in laminar
channel flow, are determined and evaluated. Experimentally
the effects of surface tension, viscosity, fluid flow rate,
density, and bubble diameter on bubble dislodgement were
evaluated. A theoretical scale analysis was performed which
provided a...
Spray impingement cooling has been shown to be a leading candidate for future high heat flux cooling applications. In general, spray cooling curves consist of three heat flux regimes; single-phase, two-phase and critical heat flux (CHF). CHF is considered the design limit for almost all two-phase cooling applications, as a...
Renewable energy sources are becoming increasingly important due to their low environmental impact and limitless nature. This thesis explores the design of a 250 mW permanent magnet linear generator wave energy converter to power ocean sensors. While many wave energy converters exist, this is a unique application because the wave...
Currently, little work has been performed studying energy consumption in hop kilning. This thesis explores drying with an alternative drying schedule that extends the initially elevated drying temperature currently used by growers and examines its impact on drying time and energy use. Extending the time of the initially elevated drying...