Bulletin of the American Physical Society
68th Annual Meeting of the APS Division of Fluid Dynamics
Volume 60, Number 21
Sunday–Tuesday, November 22–24, 2015; Boston, Massachusetts
Session M1: Industrial Applications III |
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Chair: Paul Steen, Cornell University Room: Auditorium |
Tuesday, November 24, 2015 8:00AM - 8:13AM |
M1.00001: Thermal striping in nuclear reactors: POD analysis of LES simulations and experiment Elia Merzari, Andres Alvarez, Oana Marin, Aleksandr Obabko, Steve Lomperski, Shashi Aithal Thermal fatigue caused due to thermal striping impacts design and analyses of a wide-range of industrial apparatus. This phenomena is of particular significance in nuclear reactor applications, primarily in sodium cooled fast reactors. In order to conduct systematic analyses of the thermal striping phenomena a simplified experimental set-up was designed and built at Argonne National Laboratory. In this set-up two turbulent jets with a temperature difference of about 20K were mixed in a rectangular tank. The jets entered the tank via 2 hexagonal inlets. Two different inlet geometries were studied, both experimentally and via high-fidelity LES simulations. Proper Orthogonal Decomposition (POD) was performed on the turbulent velocity field in the tank to identify the most dominant energetic modes. The POD analyses of the experimental data in both inlet geometrical configurations were compared with LES simulations. Detailed POD analyses are presented to highlight the impact of geometry on the velocity and thermal fields. These can be correlated with experimental and numerical data to assess the impact of thermal striping on the design of the upper plenum of sodium-cooled nuclear reactors. [Preview Abstract] |
Tuesday, November 24, 2015 8:13AM - 8:26AM |
M1.00002: Planar Flow Casting: Crystalline and Non-crystalline Ribbon Formation Joseph Mattson, Eric Theisen, Paul Steen Planar flow casting (PFC) is a single-stage continuous casting process used in the production of thin metallic sheets. Molten metal is ejected from a reservoir and forced through a small gap to freeze against a translating substrate. The process is typically `feed limited' which means that an imposed pressure drop determines the flow rate of metal to the solidification front, and thus the ultimate thickness of the solid sheet. Depending on the molten alloy, the substrate heat sink can provide sufficient cooling rates to produce a glassy (amorphous) metal. Otherwise, a crystalline solid is the result. In this talk, by relating ribbon thickness to residence time for both amorphous and crystalline products, we address the question: to what extent is processing `blind' to the solidification mechanism? [Preview Abstract] |
Tuesday, November 24, 2015 8:26AM - 8:39AM |
M1.00003: ABSTRACT WITHDRAWN |
Tuesday, November 24, 2015 8:39AM - 8:52AM |
M1.00004: Squeeze flow with capillary effect in Nano Imprint Lithography (NIL) process Bharath Babu Nunna, Shiqiang Zhuang, Eon Soo Lee In the Nano imprinting process, the resist forms the required nano structures upon the squeeze effect, between the polymer mold and substrate. Due to this squeeze effect the resist will experience the squeeze force, which leads the fluid (resist) to fill the cavity of the mold. But the fluid due to its natural phenomenon undergoes a capillary effect that contributes to the fluid movement. In this presentation the fluid dynamics of the resist in the cavity upon the squeeze force and capillary effect are examined in detail. The study of the resist flow in the nano imprint lithography (NIL) process helps to define the exact required squeeze force to obtain the enhanced quality of nano structures. [Preview Abstract] |
Tuesday, November 24, 2015 8:52AM - 9:05AM |
M1.00005: A comparative study of SU-8 and wax based paper-fluidic device with respect to channel geometry Jinkee Lee, Ali Turab Jafry, Hosub Lim Although many fabrication techniques of paper fluidic devices have evolved as a result of its broad application spectrum and ease of use, the technology has still barely scratched the surface of its potential in terms of its underlying fundamental principle i.e. fluid flow analysis. In this paper we have studied the comparison of flow profile attained by using two of the most promising techniques of photolithography and wax printing from a hydrodynamic point of view. A modified protocol for synthesizing an SU-8 based channel and wax based channel is created by optimizing few process parameters to our equipment. Water and oil (oleic acid) are chosen as hydrophilic and hydrophobic fluids respectively and their flow is analyzed in straight channels within paper device. A new approach to vary flow velocity is described in detail involving dots as resistance inside the paper channel. Observing the length-time curve for the two fluids, it becomes evident that both follow the Lucas-Washburn equation if the width of channel is large enough. Various configurations of dots reveal different longitudinal flow velocity implying its application in simultaneous addition of chemicals without the need to change channel width or length [Preview Abstract] |
Tuesday, November 24, 2015 9:05AM - 9:18AM |
M1.00006: Fluid Mechanics Optimising Organic Synthesis Evgenia Leivadarou, Stuart Dalziel The Vortex Fluidic Device (VFD) is a new ``green'' approach in the synthesis of organic chemicals with many industrial applications in biodiesel generation, cosmetics, protein folding and pharmaceutical production. The VFD is a rapidly rotating tube that can operate with a jet feeding drops of liquid reactants to the base of the tube. The aim of this project is to explain the fluid mechanics of the VFD that influence the rate of reactions. The reaction rate is intimately related to the intense shearing that promotes collision between reactant molecules. In the VFD, the highest shears are found at the bottom of the tube in the Rayleigh and the Ekman layer and at the walls in the Stewardson layers. As a step towards optimising the performance of the VFD we present experiments conducted in order to establish the minimum drop volume and maximum rotation rate for maximum axisymmetric spreading without fingering instability. [Preview Abstract] |
Tuesday, November 24, 2015 9:18AM - 9:31AM |
M1.00007: Microfluidic IEF technique for sequential phosphorylation analysis of protein kinases Nakchul Choi, Simon Song, Hoseok Choi, Bu-Taek Lim, Young-Pil Kim Sequential phosphorylation of protein kinases play the important role in signal transduction, protein regulation, and metabolism in living cells. The analysis of these phosphorylation cascades will provide new insights into their physiological functions in many biological functions. Unfortunately, the existing methods are limited to analyze the cascade activity. Therefore, we suggest a microfluidic isoelectric focusing technique ($\mu $IEF) for the analysis of the cascade activity. Using the technique, we show that the sequential phosphorylation of a peptide by two different kinases can be successfully detected on a microfluidic chip. In addition, the inhibition assay for kinase activity and the analysis on a real sample have also been conducted. The results indicate that $\mu $IEF is an excellent means for studies on phosphorylation cascade activity. [Preview Abstract] |
Tuesday, November 24, 2015 9:31AM - 9:44AM |
M1.00008: Capacitive Deionization: Performance Improvement Using Multistep Buffered Arrangement and Ordered Mesoporous Carbon Electrodes Yasamin Salamat, Carlos Rios Perez, Anvesh Gurijala, Randall Erb, Carlos Hidrovo Capacitive deionization (CDI) is an emerging novel technology for water treatment which uses an electrical field to adsorb ions to oppositely charged high porous media. The most distinguished feature of CDI is its ability to retrieve a fraction of the energy consumed for desalination during the regeneration cycle. Here, we propose a new architecture aiming to improve the overall performance of CDI. In this method, an array of CDI cells are connected in series with solution buffers in between them. The buffer solution homogenizes the outlet concentration of the preceding cell and supplies a constant concentration reservoir for the next cell. The performance of the proposed CDI system with two CDI cells and one solution buffer was compared with a two-cascaded-cells array with no solution buffer. The obtained results demonstrated the superiority of the proposed buffered system, in terms of desalination percentage. In addition, a new method for fabricating ordered mesoporous carbon electrodes was introduced aimed at reducing the electrical resistance of the system and enhancing its adsorption capacity. Performance of the electrodes was evaluated using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV). The proposed methods provide great potentials for CDI to be implemented in larger scales and industrial applications. [Preview Abstract] |
Tuesday, November 24, 2015 9:44AM - 9:57AM |
M1.00009: Characterization of desalination performance of CDI electrode materials using extended electroimpedance spectroscopy Carlos Rios Perez, Ellen Wilkes, Carlos Hidrovo A comprehensive characterization of porous materials developed for capacitive deionization (CDI) electrodes is very important for the future of this desalination technology. Traditional methods assess the adsorption performance of the electrodes using gas adsorption techniques and electrochemical tests. However, these results fail at comparing quantitatively the performance of different electrode materials. This presentation proposes using a combination of extended electroimpedance spectroscopy (EIS) tests and BET analysis to appraise the amount of salt adsorbed in a flow-by CDI system. The extended EIS experiments were analyzed using an equivalent circuit with three characteristic tiers that represent the dominant ionic migration processes with different time-scales: electro adsorption of ions in the micropores, migration of ion from bulk solution through macropores, adsorption of ions from the bulk solution. The results obtained show a very good agreement between characterization and desalination performance experiments for three commercial electrodes with different structure topology. [Preview Abstract] |
Tuesday, November 24, 2015 9:57AM - 10:10AM |
M1.00010: Crackle noise from high-speed free-shear-flow turbulence David Buchta, Jonathan Freund High-thrust jet engines radiate a particularly intense and distinct sound that has become known as `crackle'. Its root mechanisms are not fully understood, though they are thought to involve nonlinear acoustics because the sound waves appear steepened. They also have a positive skewness, pressure maxima are stronger than minima, for unknown reasons. We use direct numerical simulations of free-shear-flow turbulence with Mach numbers ranging from $M=0.9$ to $3.5$ to study the very near acoustic field and the turbulence interactions. Results indicate that crackle is insensitive to Reynolds number for the range considered, though DNS is restricted to modest Reynolds numbers. The very near field is teeming with weak, nonlinearly interacting Mach-like waves. Locally, these waves generate intense pressure fluctuations, especially as they merge. We observe that skewness changes are small over the propagation distances simulated, though more significant changes are to be expected over larger propagation distances. The source of the peculiar skewness is thus near or within the turbulence. Simulations modulating the underlying unstable linear modes reveal a sensitivity to crackle and are used to assess the role of large-scale structures in its source. [Preview Abstract] |
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