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Full-Text Articles in Engineering

Thermal Atomization Of Impinging Drops On Superheated Superhydrophobic Surfaces, Eric Lee May 2023

Thermal Atomization Of Impinging Drops On Superheated Superhydrophobic Surfaces, Eric Lee

Theses and Dissertations

Drop impact on a surface has an effect on nearly every industry and this impact may have adverse effects if not controlled. Superhydrophobic (SH) surfaces have been created with the extreme ability to repel water. These surfaces exist in nature but may also be fabricated using modern techniques. This thesis explores heat transfer from these SH surfaces to drops impacting them. This thesis is devoted to increasing the breadth of knowledge of thermal atomization during drop impingement on superheated SH surfaces. When a water drop impinges vertically on a horizontal superheated surface, intense atomization can occur. The atomization is caused …


Atomization Of A Liquid Water Jet In Crossflow At Varying Hot Temperatures For High-Speed Engine And Stratospheric Aerosol Injection Applications, Luke Caetano Jan 2022

Atomization Of A Liquid Water Jet In Crossflow At Varying Hot Temperatures For High-Speed Engine And Stratospheric Aerosol Injection Applications, Luke Caetano

Honors Undergraduate Theses

This paper aims to study how varying crossflow burning temperatures from 1100 C to 1800 C affect the liquid droplet breakup, size distribution, and atomization of a liquid water jet injected into a vitiated crossflow. The LJIC injection mechanism was implemented using the high-pressure axially staged combustion facility at the University of Central Florida. The measurement devices used to gather particle data from the exhaust plume were the TSI Aerodynamic Particle Sizer (APS), which measures particles between 0.523 µm and 20 µm, and the Sensirion SPS30 (SPS30), which measures particles between 0.3 µm and 10 µm. Both measurement devices were …


Thermal Atomization Due To Boiling During Droplet Impingement On Superhydrophobic Surfaces, Preston Todd Emerson Jan 2020

Thermal Atomization Due To Boiling During Droplet Impingement On Superhydrophobic Surfaces, Preston Todd Emerson

Theses and Dissertations

Superhydrophobic (SH) surfaces are characterized by their extraordinary water repellent qualities. When water comes in contact with these surfaces, it beads up and rolls around. This phenomenon is due partially to surface chemistry which promotes weak adhesive forces between liquid and solid. However, micro- and nanoscale surface roughness also plays a crucial role by trapping air beneath the liquid, reducing liquid-solid contact. Many advantages of these surfaces have been identified, including drag reduction and self-cleaning properties, and the body of research regarding them has grown rapidly over the past few decades.This thesis is concerned with water droplets impinging superheated, superhydrophobic …


Eulerian Cfd Modeling Of Multiphase Internal Injector Flow And External Sprays, Eli T. Baldwin Nov 2016

Eulerian Cfd Modeling Of Multiphase Internal Injector Flow And External Sprays, Eli T. Baldwin

Doctoral Dissertations

The improvement of combustion systems which use sprays to atomize liquid fuel requires an understanding of that atomization process. Although the secondary break up mechanisms for the far-field of an atomizing spray have been thoroughly studied and well understood for some time, understanding the internal nozzle flow and primary atomization on which the far-field spray depends has proven to be more of a challenge. Flow through fuel injector nozzles can be highly complex and heavily influenced by factors such as turbulence, needle motion, nozzle imperfections, nozzle asymmetry, and phase change. All of this occurs within metallic injectors, making experimental characterization …


Effect Of Heating And Ionization Of Four Atomizing Gases On The Spray Characteristics Of A High Volume Low Pressure Spray Atomizer, Anthony V. Adornato Jan 2015

Effect Of Heating And Ionization Of Four Atomizing Gases On The Spray Characteristics Of A High Volume Low Pressure Spray Atomizer, Anthony V. Adornato

Theses and Dissertations--Mechanical Engineering

The disintegration of a liquid jet emerging from a nozzle by a high speed gas stream has been under investigation of several decades. A result of the liquid jet disintegration is droplet formation. This process is referred to as atomization. Industrial applications use atomization as a method for applying coatings to substrates. It has been reported that the use of other atomizing gases instead of compressed plant air will positively affect paint droplet size distributions, spray patterns and finish qualities; furthermore, the ionization and heating of the atomizing gas was reported to positively affect finish qualities. Although ionization techniques have …


Analytical And Numerical Validation Of Nozzle Spray Measurement Data Obtained From A Newly Developed Production System, Iddrisu Seidu Jan 2015

Analytical And Numerical Validation Of Nozzle Spray Measurement Data Obtained From A Newly Developed Production System, Iddrisu Seidu

ETD Archive

A newly developed production test stand for measuring the spray angle of a pressure swirl atomizer was constructed and used to measure a product line of these pressure swirl atomizers -- the macrospray atomizer. This new test stand, utilizing constant temperature hot wire anemometers, captures the spray angle data based on the voltage drop the hot wire probes see as they traverse the spray cone of the atomizer and as fluid droplets impinge upon the wire. Datasets acquired from the experiments are compared and correlated with computational fluid dynamics (CFD) simulation data. In addition, angles obtained from another type of …


Towards Scalable Nanomanufacturing: Modeling The Interaction Of Charged Droplets From Electrospray Using Gpu, Weiwei Yang Jan 2012

Towards Scalable Nanomanufacturing: Modeling The Interaction Of Charged Droplets From Electrospray Using Gpu, Weiwei Yang

Electronic Theses and Dissertations

Electrospray is an atomization method subject to intense study recently due to its monodispersity and the wide size range of droplets it can produce, from nanometers to hundreds of micrometers. This thesis focuses on the numerical and theoretical modeling of the interaction of charged droplets from the single and multiplexed electrospray. We studied two typical scenarios: large area film depositions using multiplexed electrospray and fine pattern printings assisted by linear electrostatic quadrupole focusing. Due to the high computation power requirement in the unsteady n-body problem, graphical processing unit (GPU) which delivers 10 Tera flops in computation power is used to …


Design Of A Liquid Fuel Injector For Alternative Fuel Studies In An Atmospheric Model Gas Turbine Combustor, John Stevenson Jan 2011

Design Of A Liquid Fuel Injector For Alternative Fuel Studies In An Atmospheric Model Gas Turbine Combustor, John Stevenson

Honors Theses

A new liquid-fuel injector was designed for use in the atmospheric-pressure, model gas turbine combustor in Bucknell University’s Combustion Research Laboratory during alternative fuel testing. The current liquid-fuel injector requires a higher-than-desired pressure drop and volumetric flow rate to provide proper atomization of liquid fuels. An air-blast atomizer type of fuel injector was chosen and an experiment utilizing water as the working fluid was performed on a variable-geometry prototype. Visualization of the spray pattern was achieved through photography and the pressure drop was measured as a function of the required operating parameters. Experimental correlations were used to estimate droplet sizes …


Design, Development, And Analysis Of A Twin-Fluid Fire Suppression Atomizer And Characterization Of Electrostatically Charged Droplet Sprays, Chad Everett Moore Jan 2003

Design, Development, And Analysis Of A Twin-Fluid Fire Suppression Atomizer And Characterization Of Electrostatically Charged Droplet Sprays, Chad Everett Moore

LSU Master's Theses

A twin-fluid water mist fire suppression atomizer is designed, developed, and analyzed. Of primary interest is the development of a twin-fluid atomizer that produces a large droplet diameter and velocity distribution and also produces a mist with sufficient cone angle to be effective in fire suppression applications. Spray characterization experiments are conducted utilizing Phase Doppler Particle Analysis (PDPA). The effect of atomizer nozzle geometry on internal two-phase flow and resulting spray pattern is investigated. National Fire Protection Association (NFPA) Standard 750 characterization experiments are conducted to verify that the sprays produced by the developed atomizer are classified as a water …