An experimental study of the near-field flow structure produced by an incompressible turbulent Acoustically Self-Excited Jet (ASEJ) in a large enclosure using Particle Image Velocimetry (PIV) is presented. The salient feature of this jet is that it provides an increase in near-field mixing and turbulence without additional external power input....
Droplet formation from a flexible nozzle plate driven by a prescribed-waveform excitation of a piezoelectric is numerically investigated using a computational fluid dynamics (CFD) model with the VOF method. The droplet generator with a flexible nozzle plate, which is free to vibrate due to the pressure acting on the plate,...
Transportation plays such an important role in daily living that, without it, a person might be totally homebound. The nation’s air travel system for persons with disabilities is an area of substantial dissatisfaction, with both passengers and the airline industry recognizing the need for improvement. One of the major concerns...
A PID controller was designed to control the performance of an oil-heated fractal-like branching microchannel desorber for use in an ammonia-absorption refrigeration system. Both the amount and concentration of ammonia refrigerant generated at the desorber can be controlled by choosing the rectified circulation ratio as the controlled variable in a...
The behavior of a metal vapor plasma arc in a vacuum arc remelting (VAR) furnace is believed to contribute to the formation of defects in reactive metal and super-alloy ingots. Industry standard instrumentation, which includes electric current and voltage measurements, can asses the stability of an arc but cannot predict...
A Mixed Reactant Single Chamber (MRSC) Fuel Cell is a relatively recent concept in the field of fuel cell engineering originally developed in the late 1950’s. Typical fuel cells have separated reactants (a separated fuel and oxidizer) that react on their usually non-selective electro-catalytic materials. A mixed reactant fuel cell...
Coordinating multiple robots to achieve a complex task requires solving two distinct control problems: the high-level control problem of ensuring that each robot aims to perform a useful task (e.g., coordination) and the low-level control problem of ensuring that each robot actually performs the correct actions to achieve its task...
Flow separation is an important phenomenon in fluid dynamics because of the effect it has on lift and drag on immersed bodies. Areas of swirl within a separated flow region may have a distinct effect on the surface forces, modifying the lift and drag characteristics. A correlation between the passage...
A non-intrusive measurement technique for direct quantitative thermal visualization of channel wall temperatures in two phase microchannel flows using infrared thermography (IRT) is presented. Specifically, the measurement of top channel wall temperatures in a fractal-like branching microchannel silicon heat sink during flow boiling is demonstrated and thoroughly documented. Obtaining quantitative...
Field biologists are in need of more specialized and technical equipment than they are able to produce on their own in order to collect data more efficiently or gather data that is not currently available. This presents a challenge for design engineers because these products are typically highly specialized and...
Based on experimental investigations the present study evaluates flow instability and
void fraction in a fractal-like branching microchannel network with rectangular cross-section. The hydraulic diameter of the channels ranged from 308μm at the inlet to 143μm at the outlet. The flow network used is characterized by set branching ratios for...
Identification and population counts of soil mesofauna can be an
important tool for soil ecologists to determine the soil biodiversity. Information
provided from population counts can give insight to soil ecologists about the
effects of human land use, monitoring soil and water health, benefits of soil
biodiversity in agriculture, and...
An experimental study of thermally actuated pumping of a single-phase, single-component fluid is presented in the context of thermal management of a heat source. The prominent feature of this pumping method is that the very heat that is to be removed from the heat source causes a net fluid motion....
Two-phase gas-liquid flows in microscale fractal-like branching channel flow networks were experimentally studied to assess the validity of existing void fraction correlations and flow regimes based on superficial gas and liquid velocities. Void fractions were assessed using two different methods. First, void fraction data were acquired using a High-Speed-High-Resolution (HSHR)...
In many composites, fiber bridging develops as part of the fracture process. Fiber bridging invalidates many toughness evaluation methods such as the ASTM E399 and complicates the identification of crack length, which is a necessary parameter in energy methods. In order to measure the toughness of fiber bridging composites, an...
The current proliferation of portable electronic devices for personal
communication, business and entertainment has created a demand for high energy density
power supplies. A hydrocarbon fuel with a conversion efficiency of over
15% can provide greater energy density than current battery technology for these
applications. Current micro-scale heat engines do...
The thermal wave technique has been explored for the use of liquid thermal conductivity measurement and flow property diagnostics in this dissertation. For liquid thermal conductivity measurements, an experimental technique based on the thermal wave approach is developed. A stainless steel strip functions as both a heating element and a...
A one-dimensional numerical model has been developed to study diabatic and adiabatic
flow boiling in microchannels. This model accounts for developing flow effects and
variable property effects. The model uses correlations for void fraction and two-phase
multipliers found in the literature. The model has been used to study the performance...
Risk is a crucial decision factor besides traditional cost and performance during collaborative decision making in a distributed environment. Three main challenges exist: 1) stakeholders' different perspectives and/or diverse cultures can lead to inconsistent risk probability evaluations; 2) risk consequence is hard to be quantified in concrete unit; 3) risk...
At the start of the 21st century much of the focus of aircraft design has been turned to unmanned aerial vehicles (UAVs) which generally operate at much lower speeds in higher risk areas than manned aircraft. One subset of UAVs are Micro Air Vehicles (MAVs) which usually are no larger...