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Articles 1 - 13 of 13
Full-Text Articles in Engineering
Developing General Purpose Apps To Automate Image Analysis Of Wave-Augmented-Varicose-Explosion Atomization And Other Multi-Phase Interfacial Flows, Ethan Newkirk
Senior Honors Theses
Atomization involves disrupting a flow of contiguous liquid into small droplets ranging from one submicron to several hundred microns (micrometers) in diameter through the processes of exerting sufficient forces that disrupt the retaining surface tensions of the liquid. Understanding this phenomenon requires high-speed imaging from physical models or rigorous multiphase computational fluid dynamics models. We produce a MATLAB application that utilizes various methods of image analysis to quickly analyze and store mathematical data from detailed image analyses. We present a user with numerous tools and capabilities that provide results that deviate from 1.8% to 8.9% of the original image sequence …
Thermal Atomization On Superhydrophobic Surfaces Of Varying Temperature Jump Length, Eric D. Lee, Daniel Maynes, Julie Crockett, Brian D. Iverson
Thermal Atomization On Superhydrophobic Surfaces Of Varying Temperature Jump Length, Eric D. Lee, Daniel Maynes, Julie Crockett, Brian D. Iverson
Faculty Publications
This paper presents an experimental study of drop impingement and thermal atomization on hydrophobic and superhydrophobic (SH) surfaces. Superhydrophobic surfaces having both microscale and nanoscale geometry are considered. Microscale SH surfaces are coated with a hydrophobic coating and exhibit micropillars and cavities which are classified using the surface solid fraction and center to center pitch. The solid fraction and pitch values explored in this study range from 0.05-1.0 and 8-60 μm respectively. Nanoscale textured surfaces are created by applying a blanket layer of carbon nanotubes. Both types of surfaces are further classified by a temperature jump length (λ …
Imaging Diagnostics For Jet Breakup Into Droplets: A Review, Anu Osta
Imaging Diagnostics For Jet Breakup Into Droplets: A Review, Anu Osta
Henry M. Rowan College of Engineering Faculty Scholarship
A concise review of the recent developments in some of the standard optical diagnostics applied for primary jet breakup studies has been presented here. Primary breakup is the core breakup of liquid jets and sheets into droplets upon its interaction with the ambient gaseous atmosphere. This phenomenon is encountered in various aerodynamic, fluid dynamic, and combustion situations. The imaging diagnostics reviewed here include photography, high-speed imaging, shadowgraphy, digital holography, ballistic imaging, jet core illumination, thermal imaging, Mie imaging, x-ray phase contrast imaging, and laser-induced fluorescence. The advantages and limitations of each technique, their success, and future developmental trend are discussed.
Experimental And Mathematical Tools To Predict Droplet Size And Velocity Distribution For A Two-Fluid Nozzle, Sadegh Poozesh, Nelson K. Akafuah, Heather R. Campbell, Faezeh Bashiri, Kozo Saito
Experimental And Mathematical Tools To Predict Droplet Size And Velocity Distribution For A Two-Fluid Nozzle, Sadegh Poozesh, Nelson K. Akafuah, Heather R. Campbell, Faezeh Bashiri, Kozo Saito
Mechanical Engineering Faculty Publications
Despite progress in laser-based and computational tools, an accessible model that relies on fundamentals and offers a reasonably accurate estimation of droplet size and velocity is lacking, primarily due to entangled complex breakup mechanisms. Therefore, this study aims at using the integral form of the conservation equations to create a system of equations by solving which, the far-field secondary atomization can be analyzed through predicting droplet size and velocity distributions of the involved phases. To validate the model predictions, experiments are conducted at ambient conditions using water, methanol, and acetone as model fluids with varying formulation properties, such as density, …
An Integrated Computational Materials Engineering-Anchored Closed-Loop Method For Design Of Aluminum Alloys For Additive Manufacturing, Saket Thapliyal, Mageshwari Komarasamy, Shivakant Shukla, Le Zhou, Holden Hyer, Sharon Park, Yongho Sohn, Rajiv S. Mishra
An Integrated Computational Materials Engineering-Anchored Closed-Loop Method For Design Of Aluminum Alloys For Additive Manufacturing, Saket Thapliyal, Mageshwari Komarasamy, Shivakant Shukla, Le Zhou, Holden Hyer, Sharon Park, Yongho Sohn, Rajiv S. Mishra
Mechanical Engineering Faculty Research and Publications
A closed-loop approach based on integrated computational material engineering was used to design, fabricate and characterize an Al–1.5Cu–0.8Sc–0.4Zr (wt%) alloy for laser powder bed fusion additive manufacturing (AM). Finalization of composition and prediction of solidification behavior and mechanical properties were done using calculation of phase diagrams (CALPHAD) and analytical tools. The microstructure of the printed alloy in as-built condition consisted of crack-free regions with fine-equiaxed grains which was consistent with CALPHAD results. Yield strength (YS) of ~349 ± 8 MPa was also in more than 90% agreement with predicted YS. The findings demonstrate an efficient methodology for application-based alloy design …
Study Of Near-Cup Droplet Breakup Of An Automative Electrostatic Rotary Bell (Esrb) Atomizer Using High-Speed Shadowgraph Imaging, Jacob E. Wilson, Stephen William Grib, Adnan Darwish Ahmad, Michael W. Renfro, Scott A. Adams, Ahmad Salaimeh
Study Of Near-Cup Droplet Breakup Of An Automative Electrostatic Rotary Bell (Esrb) Atomizer Using High-Speed Shadowgraph Imaging, Jacob E. Wilson, Stephen William Grib, Adnan Darwish Ahmad, Michael W. Renfro, Scott A. Adams, Ahmad Salaimeh
Mechanical Engineering Faculty Publications
Electrostatic Rotary bell (ESRB) atomizers are used as the dominant means of paint application by the automotive industry. They utilize the high rotational speed of a cup to induce primary atomization of a liquid along with shaping air to provide secondary atomization and transport. In order to better understand the fluid breakup mechanisms involved in this process, high-speed shadowgraph imaging was used to visualize the edge of a serrated rotary bell at speeds varying between 5000 and 12,000 RPM and with a water flow rate of 250 ccm. A multi-step image processing algorithm was developed to differentiate between ligaments and …
Eulerian Cfd Modeling Of Multiphase Internal Injector Flow And External Sprays, Eli T. Baldwin
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
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
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
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
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 …
Numerical Modeling For Atomization Of Coaxial Liquid/Gas Jets, Stephen Gen-Ken Chuech, Andrzej J. Przekwas, Chih-Yuan Wang
Numerical Modeling For Atomization Of Coaxial Liquid/Gas Jets, Stephen Gen-Ken Chuech, Andrzej J. Przekwas, Chih-Yuan Wang
Journal of Marine Science and Technology
In the present study, the atomization of a coaxial injector in the liquid/gas engine combustor was numerically investigated. Based on the wave instability analysis of the interface between liquid and gas, an atomization model for the high-speed liquid jets was established by coupling with the jet flow solutions. First, the wave instability was analyzed to predict the growth rates along the liquid jet surface by numerically solving the wave dispersion equation, while the governing equations of the liquid flow were solved for the formation of the liquid jet core and the variation of the liquid flow structure. Then, these two …
Design, Development, And Analysis Of A Twin-Fluid Fire Suppression Atomizer And Characterization Of Electrostatically Charged Droplet Sprays, Chad Everett Moore
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 …