Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 65 for “"bubble dynamics"”.
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Bubble dynamics in polymeric foams
… of fluid viscoelasticity on the expansion of gas bubbles in polymer foams for both non-reactive and reactive polymers are investigated. Polymer foams are used extensively in consumer products, from car parts to upholstery. They are produced either by injection moulding (of non-reactive polymeric …
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Computations of bubble dynamics with heat transfer
… the heat transfer enhancement caused by air bubble motion is of practical interest in many industrial applications ranging from boiling solar collectors to nuclear reactors. A bubble sliding over a heated obstacle increases heat transfer by displacing liquid, particularly in the wake region …
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Bubble dynamics on structured surface in microchannel
… performance is still unclear. In this thesis, bubble dynamics on micropillar array surfaces were studied. A surface energy based model is presented to predict the bubble morphology on pillar array surfaces. The results showed that bubbles tend to stay on top surfaces of pillars at solid …
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On bubble dynamics and gas dynamics in open tubes
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1997.
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Non-linear, non-spherical bubble dynamics near a two fluid interface
The interactions of bubbles with rigid and free boundaries have been well documented. Toroidal bubble formation has been observed, with jetting directed toward and away from the two types of interface respectively. This work generalises these interactions by studying the effect of a two fluid …
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Physics-constrained machine learning strategies for turbulent flows and bubble dynamics
Machine learning (ML) has in recent years become a sizzling trend in almost every science and engineering discipline. It enables scientists and engineers to make decisions or draw conclusions directly using information extracted from data, bypassing the necessity to unravel the delicate inner …
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AN EXPERIMENTAL AND NUMERICAL STUDY ON CAVITATION BUBBLE DYNAMICS AND ITS BIOMEDICAL APPLICATIONS
A thorough understanding of cavitation bubble dynamics is critical to mitigate cavitation damage or develop practical applications. An important field of study is the interaction of a single cavitation bubble with neighbouring structure(s). A cavitation bubble collapse near a finite elastic beam, …
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Long-Pulsed Laser-Induced Cavitation: Laser-Fluid Coupling, Phase Transition, and Bubble Dynamics
… mechanism behind the formation of non-spherical bubbles induced by long-pulsed lasers. The proposed computational method accounts for the laser emission and absorption, phase transition, and the dynamics and thermodynamics of a two-phase fluid flow. In this new method, the model combines the …
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Bubble Dynamics and Dense Phase Composition in 2-D Binary Gas-Solid Fluidized Bed
… (2D) fluidized bed was used to study bubble dynamics and dense phase composition distribution in order to gain some fundamental understanding of this system. Digital image analysis (DIA) was employed to measure bubble diameter, bubble rise velocity, bed expansion and particle …
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The Effects of Vortex Generator Jet Frequency, Duty Cycle, and Phase on Separation Bubble Dynamics
… profile, which has a non-reattaching separation bubble beginning at 68% axial chord. Two VGJ pulse histories were created with different frequencies, jet durations, and duty cycles. The mechanisms responsible for boundary layer separation control were shown to be a combination of boundary layer …
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Heat transfer and bubble dynamics in bubble and slurry bubble columns with internals for Fischer-Tropsch synthesis of clean alternative fuels and chemicals
… Fischer-Tropsch (F-T) synthesis process. Slurry bubble column reactor is the reactor of choice for the commercialization of the F-T synthesis. Even though the slurry bubble column reactors and contactors are simple in structures, their design, scale-up, operation, and performance prediction are …
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Hydrodynamics and Mass Transfer in Bubble Columns
<p>Bubble columns and slurry bubble columns are multiphase reactors used for a wide range of applications in the biochemical, chemical, petrochemical, and metallurgical industries. In spite of their widespread usage, the scale-up of bubble columns remains an ongoing challenge. Various scale-up …
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Modeling of Multi-Component Fuel Vaporization for Spray Simulations Using Continuous Thermodynamics
A preliminary study on drop-bubble dynamics and instability with Marangoni effects is also given. This issue is motivated by its potential application for improving air-fuel mixing and understanding the possible drop-bubble breakup mechanism.
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Micro and nanostructured surfaces for enhanced phase change heat transfer
… with flow instabilities due to insufficient bubble removal, leading to liquid dry-out which severely limits the heat removal efficiency. To address this challenge, we propose to incorporate micro/nanostructures to stabilize and enhance two-phase microchannel flows. Towards this goal, this …
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Infrared Thermometry Analysis of Surface Effects in Subcooled and Saturated Boiling of Water
In this work, the dynamics of subcooled and saturated flow boiling are studied, focusing on the influence of surface characteristics, visualized through advanced diagnostics capturing micro-scale phenomena. Utilizing specially crafted thin-film infrared heaters, we measured bubble dynamics …
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Behaviour of Bubble Columns with Two and Three Phases
Bubble columns are multi-phase contactors widely used in the process industries. For proper design, effective operation and analysis of such columns, knowledge of the fluid-dynamics, mixing and transport parameters is essential. Hitherto, most studies have been on simple two-phase systems in …
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The extrusion processing of instant coffee for the purposes of creating a pressurised microstructure
… of a model for the dynamic behaviour of gas bubbles in molten instant coffee, in response to changes in pressure and temperature. Initially, the material properties of molten instant coffee were investigated. The primary technique used was capillary rheometry, as the viscous behaviour of …
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Ultrasonic Effervescence: Investigations of the Nucleation and Dynamics of Acoustic Cavitation for Histotripsy-Based Therapies
… adequate number of applied pulses, cavitation "bubble clouds" create precise lesions with high fidelity to the region of the focus. Despite advances in histotripsy, additional research is still needed to better understand the acoustic cavitation nucleation process and its effects on therapies …
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Microbubble streaming flows for non-invasive particle manipulation and liquid mixing
… length scale shrinks, the synergy of micro-hydrodynamics with various external force fields (capillary forces, acoustic forces, electric and magnetic fields, and optical forces) has emerged as an exciting inter-disciplinary field. In this dissertation, we study an emerging actuating mechanism -- …
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Fluid Dynamics And Scale-Up Of Bubble Columns With Internals
Bubble columns and slurry bubble columns, as multiphase reactors, are favored for a wide range of applications in the chemical, biochemical, petrochemical and metallurgical industries. They are considered the reactor of choice for the Fischer Tropsch synthesis, among other applications, offering an …
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