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Filtering by: Dspace Collection Electronic Theses and Dissertations Remove constraint Dspace Collection: Electronic Theses and Dissertations Advisor Liburdy, James A. Remove constraint Advisor: Liburdy, James A. Degree Field Mechanical Engineering Remove constraint Degree Field: Mechanical Engineering

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  • Lift and drag characteristics of flexible pitching and heaving wings

    Creator:
    Rushen, Jesse
    Abstract:
    There is a pressing need for Micro Air Vehicles (MAV) that are light, powerful, and efficient to perform military reconnaissance missions and search and rescue operations. These MAVs have length scales on the order of 10 cm, where traditional steady flight wing designs perform poorly. An alternative flight mechanism is...
    Resource Type:
    Masters Thesis
    Full Text:
    and heave the wings over a range of conditions. The forces on these wings were measured with a pair

  • Heat transfer during the piston-cylinder expansion of a gas

    Creator:
    Rodrigues, Matthew Jose
    Abstract:
    The expansion of a gas within a piston-cylinder arrangement is studied in order to obtain a better understanding of the heat transfer which occurs during this process. While the situation of heat transfer during the expansion of a gas has received considerable attention, the process is still not very well...
    Resource Type:
    Masters Thesis
    Full Text:
    experiments justify the polytropic expansion assumption, and from these results models are developed for the

  • The experimental characterization of membrane behavior in two-phase gas extraction

    Creator:
    Cappello, Nicholas C.
    Abstract:
    Understanding the behavior of hydrophobic membranes is important for applications where separating a gas from a liquid-gas mixture is beneficial. For example, in-situ vapor extraction can be used in microscale heat sinks to improve heat transfer and flow stability. In this study, gas is experimentally evaluated flowing through flexible polytetrafluoroethylene...
    Resource Type:
    Masters Thesis
    Full Text:
    -up. 38 4.2 Single-phase and two-phase cases, some cells are empty because these variables are not

  • Modeling convective boiling flow with in-situ local vapor extraction

    Creator:
    Salakij, Saran
    Abstract:
    The pressure drop of convective boiling flow may be reduced by extracting vapor locally since the entire generated vapor does not have to travel through the entire channel length. In this study, the theoretical model was developed to simulate a convective boiling flow through a fractal-like branching microchannel network with...
    Resource Type:
    Masters Thesis
    Full Text:
    pressure was modified and the code rerun. This process was repeated until the exit pressures agree. These

  • A study of adiabatic and diabatic flow boiling in parallel microchannels and fractal-like branching microchannels

    Creator:
    Daniels, Brian J.
    Abstract:
    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...
    Resource Type:
    Dissertation
    Full Text:
    fractal-like branching channels are also reported. These results include channel pressure drop and void

  • Characterization of flow boiling in a fractal–like branching microchannel network

    Creator:
    Edward, Lee M.
    Abstract:
    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...
    Resource Type:
    Masters Thesis
    Full Text:
    between the air core of the channel and the wall of the channel. Generally these bubbles appear to

  • Numerical study of droplet formation with nozzle dynamics and multiple droplet impingement

    Creator:
    Sangplung, Saangrut
    Abstract:
    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,...
    Resource Type:
    Dissertation
    Full Text:
    and dynamic viscosity. These characteristics include spreading ratio, spreading velocity, and a

  • Effect of PZT driving waveform and frequency on meniscus shape and dropon-demand droplet formation parameters

    Creator:
    Yang, Guozhong
    Abstract:
    For piezoelectric stack (PZT) driven droplet generator, the driving waveform and driving frequency effect on liquid filament shape and droplet characteristics have been experimentally studied. The experimental study was based on a PZT driven droplet generator with known geometric design parameters and working fluid properties. A lumped-element-model (LEM) constructed to...
    Resource Type:
    Dissertation
    Full Text:
    particle disposing and three-dimensional printing. All these applications require the droplet generator

  • Effects of a thin, flexible nozzle on droplet formation and impingement

    Creator:
    Hawke, Shane R.
    Abstract:
    The droplet formation process in the vicinity of the nozzle exit and the behavior of a spreading droplet during impingement on a smooth glass surface were studied. Two nozzle geometries were tested. The first case was a stiff stainless steel nozzle plate 0.787 mm thick. The second case was a...
    Resource Type:
    Masters Thesis
    Full Text:
    liquid (on the order of nanoliters) quickly and precisely. All of these applications have similar

  • Modeling in-situ vapor extraction during flow boiling in microscale channel

    Creator:
    Salakij, Saran
    Abstract:
    In-situ vapor extraction is performed by applying a pressure differential across a hydrophobic porous membrane that forms a wall of the channel as a means of reducing the local quality of flow boiling within the channel. As the local quality is reduced, the heat transfer capability can be improve while...
    Resource Type:
    Dissertation
    Full Text:
    and miniaturization of electronic devices in the last few decades, the large increase in heat