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 27 for “"liquid-vapor interface"”.
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Probing the liquid-vapor interface in microstructured heat exchangers
… aspects of a project designed to understand the liquid-vapor interface in microstructured heat exchangers. The two aspects include: design and fabrication of a custom vacuum chamber faceplate and the investigation of the liquid meniscus shape on microstructured devices. The faceplate for the …
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Kinetics of Heat and Mass Transfer Near the Liquid-Vapor Interface
Evaporation and condensation can be seen in our daily lives but also play a key role in technologies that drive our modern society, such as power generation, distillation, refrigeration, and thermal management for buildings and electronics. Over the past century, great advances have been made in …
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Removal of Bacteria from Solids by Bubbles: Effect of Solid Wettability, Interaction Geometry, and Liquid–Vapor Interface Velocity
… a bubble collides with a solid, an air–water interface crosses the solid twice, and we were able to distinguish the effects of the first and second air–water interface. The bacterium Pseudomonas aeruginosa was allowed to adhere to smooth polydimethylsiloxane (PDMS) and then a collision with a …
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Numerical Study of Fully Developed Laminar and Turbulent Flow Through Microchannels with Longitudinal Microstructures
… and the contact area between the flowing liquid and the solid wall is greatly reduced. Further, due to the scale of the micropatterned structures, the liquid is unable to wet the cavity and a liquid meniscus is formed between ribs. This creates a liquid-vapor interface at the cavity …
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Contact angle hysteresis and the energy principle
… or heterogeneity on quasi-static motion of a liquid/vapor/solid contact line. We determine the static stable equilibrium configuration(s) of the liquid/vapor interface in a system by minimizing the sum of the Helmholtz free energy and gravitational potential energy (or the total energy) of the …
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Stratification in Drying Particle Suspensions
… the structure of the dry film depends on the evaporation rate of the solvent and the initial volume fractions of the nanoparticles. My simulation results show that the particle mixtures stratify according to their sizes when the suspensions are quickly dried, consistent with the prediction of …
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Droplet repellency of microfabricated surfaces in saturated environments
… apparent contact angles for droplets of various liquids on microstructured surfaces in saturated environments. Micro scale pillar surfaces maintain the non-wetting Cassie-Baxter regime for drops of water over a range of saturation temperatures while micro scale waffles transition into a partially …
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Analysis of Viscous Drag Reduction and Thermal Transport Effects for Microengineered Ultrahydrophobic Surfaces
… for reducing the frictional resistance to liquid flow in microchannels is the patterning of micro-ribs and cavities on the channel walls. When treated with a hydrophobic coating, the liquid flowing in the microchannel wets only the top surfaces of the ribs, and does not penetrate into the …
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Experimental Study of Wall Shear Stress Modification by Surface Coating: Pressure Drop Measurements in a Rectangular Channel
… are further proof of the importance of a liquid-vapor interface for increasing the shear free area to produce drag reduction.
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Molecular Interfaces and Heterogeneous Bubble Nucleation From Heated Surfaces At Nanoscale
… various underlying phenomena of thin-film evaporation, boiling, condensation, surface wetting, and droplet evaporation. Several studies show that heat transfer can be enhanced significantly by incorporating micro and nanoscale features onto surfaces. Phase change heat transfer plays an …
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Heat transfer through a condensate droplet on hydrophobic and nanostructured superhydrophobic surfaces
… the fundamental mechanisms governing vapor condensation on non-wetting surfaces is crucial to a wide range of energy and water applications. In this thesis, we reconcile classical droplet growth modeling barriers by utilizing two-dimensional axisymmetric numerical simulations to study …
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Fabrication of a nanoporous membrane device for high heat flux evaporative cooling
… performance integrated circuits. The biporous evaporation device utilizes thermally-connected, mechanically-supported, high capillarity membranes that maximize thin film evaporation and high permeability liquid supply channels that allow for lower viscous pressure losses. The 600 nm thick …
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Design and modeling of a high flux cooling device based on thin film evaporation from thin nanoporous membranes
… to address these thermal management needs is liquid vapor phase-change. In this thesis, we present a study into the design and modeling of a cooling device based on thin film evaporation from a nanoporous membrane supported on microchannels. The concept utilizes the capillary pressure …
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Experimental Study of Meniscus Thin-Film Evaporation in a Horizontal-Tube, Falling-Film Heat Exchanger, Focusing on Dynamic Contact Angle Variation of an Advancing Meniscus
… dynamics were studied with respect to thin-film evaporation, specifically focusing on a horizontal-tube, falling-film heat exchanger. Experiments were carried out investigating the effects of solution subcooling, evaporator wall superheat, and porous-layer coating on the portions of sensible and …
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Molecular Structure and Thermodynamics of CO<sub>2</sub> and Water Adsorption on Mica
… Here, the adsorption of CO2 and water vapor is studied using Grand Canonical Monte Carlo and molecular dynamics simulations. At a bulk pressure of 100 bar, pure CO2 adsorbs strongly on mica and forms extensive layers next to it. CO2 adsorption is lowered substantially if introducing …
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Contact Angle Of A Nano-Drop On A Heterogeneous Surface
… surface tension, at the three phase solid liquid vapor interface, and contact angle on a homogeneous surface. Cassie and Baxter generalized this equation to heterogeneous surfaces implying that contact angle corresponds to the average properties of the surface under the drop. McCarthy and …
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Steady State Mathematical Modeling of Non-Conventional Loop Heat Pipes: A Parametric and a Design Approach
… a conventional LHP, the pressure drop across the liquid-vapor interface in the evaporator wick is not very high. In the present work, two different mathematical models – a parametric model and a design model, are developed. The device is partitioned into three prominent sections – the evaporator, …
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Evaporation from nanopores : probing interfacial transport
Evaporation, a commonly found phenomenon in nature, is widely used in thermal management, water purification, and steam generation as it takes advantage of the enthalpy of vaporization. Despite being extensively studied for decades, the fundamental understanding of evaporation, which is necessary …
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An investigation of droplets and films falling over horizontal tubes
<p>Liquid films falling over horizontal-tube banks are frequently utilized in absorption heat pumps, heat-driven systems that provide an environmentally and economically attractive alternative to conventional CFC-based vapor compression cycles in certain applications. The widespread application of …
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Molecular design of interfacial modifications to alter adsorption/desorption equilibria at fluid-adjoining interfaces
… kinetics of adsorption and desporption at interfaces play vital roles in chemical analysis, separation processes, and many natural phenomena. In this work, computer simulations were used to design interfacial modifications to alter the physical processes of adsorption and desorption, using …
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