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- Mechanical and Materials Engineering Faculty Publications and Presentations (7)
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Articles 1 - 15 of 15
Full-Text Articles in Engineering
The Ejection Of Large Non-Oscillating Droplets From A Hydrophobic Wedge In Microgravity, Logan Torres, Mark M. Weislogel
The Ejection Of Large Non-Oscillating Droplets From A Hydrophobic Wedge In Microgravity, Logan Torres, Mark M. Weislogel
Mechanical and Materials Engineering Faculty Publications and Presentations
When confined within containers or conduits, drops and bubbles migrate to regions of minimum energy by the combined effects of surface tension, surface wetting, system geometry, and initial conditions. Such capillary phenomena are exploited for passive phase separation operations in micro-fluidic devices on earth and macro-fluidic devices aboard spacecraft. Our study focuses on the migration and ejection of large inertial-capillary drops confined between tilted planar hydrophobic substrates (a.k.a., wedges). In our experiments, the brief nearly weightless environment of a 2.1 s drop tower allows for the study of such capillary dominated behavior for up to 10 mL water drops with …
The Draining Of Capillary Liquids From Containers With Interior Corners Aboard The Iss, Joshua Thomas Mccraney, Mark M. Weislogel, Paul Steen
The Draining Of Capillary Liquids From Containers With Interior Corners Aboard The Iss, Joshua Thomas Mccraney, Mark M. Weislogel, Paul Steen
Mechanical and Materials Engineering Faculty Publications and Presentations
In this work, we analyze liquid drains from containers in effective zero-g conditions aboard the International Space Station (ISS). The efficient draining of capillary fluids from conduits, containers, and media is critical in particular to high-value liquid samples such as minuscule biofluidics processing on earth and enormous cryogenic fuels management aboard spacecraft. The amount and rate of liquid drained can be of key concern. In the absence of strong gravitational effects, system geometry, and liquid wetting dominate capillary fluidic behavior. During the years 2010–2015, NASA conducted a series of handheld experiments aboard the ISS to observe “large” length scale capillary …
Openfoam Simulations Of Late Stage Container Draining In Microgravity, Joshua Thomas Mccraney, Mark M. Weislogel, Paul Steen
Openfoam Simulations Of Late Stage Container Draining In Microgravity, Joshua Thomas Mccraney, Mark M. Weislogel, Paul Steen
Mechanical and Materials Engineering Faculty Publications and Presentations
In the reduced acceleration environment aboard orbiting spacecraft, capillary forces are often exploited to access and control the location and stability of fuels, propellants, coolants, and biological liquids in containers (tanks) for life support. To access the ‘far reaches’ of such tanks, the passive capillary pumping mechanism of interior corner networks can be employed to achieve high levels of draining. With knowledge of maximal corner drain rates, gas ingestion can be avoided and accurate drain transients predicted. In this paper, we benchmark a numerical method for the symmetric draining of capillary liquids in simple interior corners. The free surface is …
Capillary-Tube Package Devices For The Quantitative Performance Evaluation Of Nuclear Magnetic Resonance Spectrometers And Pulse Sequences, Lingyu Chi, Ming Huang, Annalise R. Pfaff, Jie Huang, Rex E. Gerald Ii, Klaus Woelk
Capillary-Tube Package Devices For The Quantitative Performance Evaluation Of Nuclear Magnetic Resonance Spectrometers And Pulse Sequences, Lingyu Chi, Ming Huang, Annalise R. Pfaff, Jie Huang, Rex E. Gerald Ii, Klaus Woelk
Electrical and Computer Engineering Faculty Research & Creative Works
With the increased sensitivity of modern nuclear magnetic resonance (NMR) spectrometers, the minimum amount needed for chemical-shift referencing of NMR spectra has decreased to a point where a few microliters can be sufficient to observe a reference signal. The reduction in the amount of required reference material is the basis for the NMR Capillary-tube Package (CapPack) platform that utilizes capillary tubes with inner diameters smaller than 150 µm as NMR-tube inserts for external reference standards. It is shown how commercially available electrophoresis capillary tubes with outer diameters of 360 µm are filled with reference liquids or solutions and then permanently …
Deformation Of A Ferrofluid Droplet In Simple Shear Flows Under Uniform Magnetic Fields, Md Rifat Hassan, Jie Zhang, Cheng Wang
Deformation Of A Ferrofluid Droplet In Simple Shear Flows Under Uniform Magnetic Fields, Md Rifat Hassan, Jie Zhang, Cheng Wang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
We numerically investigate the deformation and orientation of a ferrofluid droplet in a simple shear flow under a uniform magnetic field. The numerical simulation is based on the finite element method and couples the magnetic and flow fields. A level set method is used to model the dynamic motion of the droplet interface. Systematic numerical simulations are used to assess the effects of the direction and the strength of the magnetic field. Focusing on low Reynolds number flows (Re ≲ 0.02), the numerical results indicate that at a small capillary number (Ca ≈ 0.02), the magnetic field dominates over the …
Controlled Manipulation Of Floating Objects On Deformed Fluid Interfaces And Conditions For Stable Equilibria, Jose M. Carballo, Qi Ni, Jose Vasquez, Nathan B. Crane
Controlled Manipulation Of Floating Objects On Deformed Fluid Interfaces And Conditions For Stable Equilibria, Jose M. Carballo, Qi Ni, Jose Vasquez, Nathan B. Crane
Faculty Publications
At the millimeter scale, interactions between floating and semi-immersed objects are significant. The local curvature of the interface is modified by the weight/buoyancy forces of floating objects, and by the surface properties of semi-immersed objects. The curvature changes generate attractive (or repulsive) interactions between floating parts, and semi-immersed objects. This work demonstrates how electrowetting can manipulate these interactions in order to position, align, assemble and transport parts attached to the fluid interface. This demonstrates one way in which fluid interfaces can provide an alternative to standard pick and place technology for part positioning/assembly. Typically, the part/rod forces are purely attractive …
Influence Of Dynamic Factors On Nonwetting Fluid Snap-Off In Pores, Wen Deng, Matthew Balhoff, M. Bayani Cardenas
Influence Of Dynamic Factors On Nonwetting Fluid Snap-Off In Pores, Wen Deng, Matthew Balhoff, M. Bayani Cardenas
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Snap-off is an important dynamic multiphase flow phenomenon which occurs in porous media. It plays a dominant role in the residual trapping and mobilization/immobilization of nonwetting fluids such as hydrocarbons or CO₂. Current studies, applications, and threshold criteria of snap-off are mostly based on static or equilibrium conditions. Thus, the dynamics of snap-off which is relevant for many real world applications has rarely been systematically studied. While a static criterion indicates the snap-off potential for nonwetting fluids, the competition between the time required for snap-off and the local pore throat capillary number determines whether snap-off actually occurs. Using a theoretical …
Evidence Of The Harmonic Faraday Instability In Ultrasonic Atomization Experiments With A Deep, Inviscid Fluid, Andrew P. Higginbotham '09, Aaron Guillen '11, Nathan C. Jones '10, Thomas D. Donnelly, Andrew J. Bernoff
Evidence Of The Harmonic Faraday Instability In Ultrasonic Atomization Experiments With A Deep, Inviscid Fluid, Andrew P. Higginbotham '09, Aaron Guillen '11, Nathan C. Jones '10, Thomas D. Donnelly, Andrew J. Bernoff
All HMC Faculty Publications and Research
A popular method for generating micron-sized aerosols is to submerge ultrasonic (ω~MHz) piezoelectric oscillators in a water bath. The submerged oscillator atomizes the fluid, creating droplets with radii proportional to the wavelength of the standing wave at the fluid surface. Classical theory for the Faraday instability predicts a parametric instability driving a capillary wave at the subharmonic (ω/2) frequency. For many applications it is desirable to reduce the size of the droplets; however, using higher frequency oscillators becomes impractical beyond a few MHz. Observations are presented that demonstrate that smaller droplets may also be created by …
Numerical Simulation Of Gas-Phonon Coupling In Thermal Transpiration Flows, Xiaohui Guo, Dhruv Singh, Jayathi Murthy, Alina A. Alexeenko
Numerical Simulation Of Gas-Phonon Coupling In Thermal Transpiration Flows, Xiaohui Guo, Dhruv Singh, Jayathi Murthy, Alina A. Alexeenko
PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems
Thermal transpiration is a rarefied gas flow driven by a wall temperature gradient and is a promising mechanism for gas pumping without moving parts, known as the Knudsen pump. Obtaining temperature measurements along capillary walls in a Knudsen pump is difficult due to extremely small length scales. Meanwhile, simplified analytical models are not applicable under the practical operating conditions of a thermal transpiration device, where the gas flow is in the transitional rarefied regime. Here, we present a coupled gas-phonon heat transfer and flow model to study a closed thermal transpiration system. Discretized Boltzmann equations are solved for molecular transport …
Gravity Effects On Capillary Flows In Sharp Corners, Enrique Ramé, Mark M. Weislogel
Gravity Effects On Capillary Flows In Sharp Corners, Enrique Ramé, Mark M. Weislogel
Mechanical and Materials Engineering Faculty Publications and Presentations
We analyze the effect of gravity on capillary flows in sharp corners. We consider gravity perpendicular and parallel to the channel axis. We analyze both steady and unsteady flows. In the steady analysis the main result is a closed form expression for the flow rate as a function of the two gravity components. Good agreement with steady experiments is offered as support of the model. The unsteady analysis is restricted to “small” values of the two gravity parameters and is accomplished using a similarity formulation. The similarity coefficients of the gravity corrections are fully determined by the coefficients of the …
Capillary-Driven Flows Along Rounded Interior Corners, Yongkang Chen, Mark M. Weislogel, Cory L. Nardin
Capillary-Driven Flows Along Rounded Interior Corners, Yongkang Chen, Mark M. Weislogel, Cory L. Nardin
Mechanical and Materials Engineering Faculty Publications and Presentations
The problem of low-gravity isothermal capillary flow along interior corners that are rounded is revisited analytically in this work. By careful selection of geometric length scales and through the introduction of a new geometric scaling parameter Tc, the Navier–Stokes equation is reduced to a convenient∼O(1) form for both analytic and numeric solutions for all values of corner half-angle α and corner roundedness ratio λ for perfectly wetting fluids. The scaling and analysis of the problem captures much of the intricate geometric dependence of the viscous resistance and significantly reduces the reliance on numerical data compared with several previous solution methods …
Dynamic Contact Angles Under Evaporation, Robert M. Ybarra, Partho Neogi
Dynamic Contact Angles Under Evaporation, Robert M. Ybarra, Partho Neogi
Chemical and Biochemical Engineering Faculty Research & Creative Works
Wetting kinetics in the presence of heat transfer, evaporation, and Marangoni effect has been explored using a method used by Joanny and de Gennes [C. R. Acad. Sci. Ser. II 299, 279 (1984)]. The method solves for the dynamic contact angle alpha by equating the rate of surface work to the rate of dissipation. The result in the form of dynamic contact angle alpha as a function of capillary number Ca agrees well with existing experimental data. Qualitative comparisons have been made in cases where quantitative data do not exist. Finally, a form of contact line instability is predicted, for …
Capillary Flow In Interior Corners: The Infinite Column, Mark M. Weislogel
Capillary Flow In Interior Corners: The Infinite Column, Mark M. Weislogel
Mechanical and Materials Engineering Faculty Publications and Presentations
Capillary flow of a sinusoidally perturbed liquid column in an interior corner of infinite extent is solved using lubrication theory. Due primarily to the length scales selected to nondimensionalize the momentum equation, an analytic time scale governing the settling of the perturbation is determined. The time scale, which is shown to be independent of a steady base state flow, proves useful in rapidly predicting transients for surface settling in certain liquid-bearing tanks of spacecraft employing interior corners for fluids management purposes. The asymptotic analysis is extended to address flows along interior corners whose faces are slightly nonplanar. The generalized formulation …
Amplitude Modulated Droplet Formation In High Precision Solder Droplet Printing, Qingbin Liu, M. Orme, Ming-Chuan Leu
Amplitude Modulated Droplet Formation In High Precision Solder Droplet Printing, Qingbin Liu, M. Orme, Ming-Chuan Leu
Mechanical and Aerospace Engineering Faculty Research & Creative Works
There are many methods used at present to apply solder to wafers, ceramics, laminate and flex circuit boards, and other substrates. Among these, high-precision solder droplet printing technology, which is noncontact, data driven, flexible and environmentally friendly, is a key enabling technology. This technology selectively deposits solder droplets only where required, and therefore needs no mask or secondary resist removal, uses materials more efficiently and creates less waste than other methods. Currently, continuous droplet formation from capillary streams is mainly achieved by application of the well-known Rayleigh instability in which a sinusoidal disturbance is applied to the stream, resulting in …
Capillary Surfaces In An Exotic Container: Results From Space Experiments, Paul Concus, Robert Finn, Mark M. Weislogel
Capillary Surfaces In An Exotic Container: Results From Space Experiments, Paul Concus, Robert Finn, Mark M. Weislogel
Mechanical and Materials Engineering Faculty Publications and Presentations
Experimental results from the Interface Configuration Experiment (ICE) performed aboard the Space Shuttle and the Mir Space Station are reported. The experiment concerns fluid interfaces in certain ‘exotic’ containers in a low-gravity environment. These containers are rotationally symmetric and have the property that for given contact angle and liquid volume, a continuum of distinct rotationally symmetric equilibrium configurations can appear, all of which have the same mechanical energy. These symmetric equilibrium configurations are unstable, in that deformations that are not rotationally symmetric can be shown mathematically to yield configurations with lower energy. It is found experimentally, in confirmation of mathematical …