Bulletin of the American Physical Society
APS March Meeting 2015
Volume 60, Number 1
Monday–Friday, March 2–6, 2015; San Antonio, Texas
Session Q18: Invited Session: Recent Advances in Field-Responsive Fluids and Suspensions |
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Sponsoring Units: DFD GSOFT Chair: Rongjia Tao, Temple University Room: Mission Room 103A |
Wednesday, March 4, 2015 2:30PM - 3:06PM |
Q18.00001: Complex magnetic fields breathe life into fluids Invited Speaker: James Martin There are many areas of science and technology where being able to generate vigorous, \textit{noncontact} flow would be desirable. We have discovered that three dimensional, time-dependent electric or magnetic fields having key symmetries can be used to generate controlled fluid motion by the continuous injection of energy [1-8]. Unlike natural convection, this approach does not require a thermal gradient as an energy source, nor does it require gravity, so space applications are feasible. The result is a highly active material we call a \textit{vortex} fluid. The homogeneous torque density of this fluid enables it to climb walls, induce ballistic droplet motion, mix vigorously, even in such complex geometries as porous media, and effect highly efficient heat transfer. This vortex fluid can also exhibit a \textit{negative} viscosity, which can immeasurably extend the control range of the ``smart fluids'' used in electro- and magnetorheological devices and can thus significantly increase their performance. Because the applied fields are uniform and modest in strength, vortex fluids of any scale can be created, making applications of any size, from directing microdroplet motion to controlling damping in magneto-rheological dampers that protect bridges and buildings from earthquakes, feasible. Finally, we will demonstrate that such fields can animate fluids in remarkable ways that resemble living systems. \\[4pt] Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. \\[4pt] [1] Martin, J. E. (2009) \textit{Phys. Rev. E} \textbf{79} 011503.\\[0pt] [2] Martin, J. E., Shea-Rohwer, L., Solis, K. J., (2009) \textit{Phys. Rev. E} \textbf{80} 016312.\\[0pt] [3] Solis, K. J., Bell, R. C., Martin, J. E., (2010) \textit{J. Appl. Phys}. \textbf{107} 114911.\\[0pt] [4] Solis, K. J., Martin, J. E., (2010) \textit{Appl. Phys. Lett}. \textbf{97}, 034101.\\[0pt] [5] Solis, K. J., Martin, J. E., (2012)\textit{ Soft Matter} \textbf{8}, 11989.\\[0pt] [6] Solis, K. J., Martin, J. E., (2012) \textit{J. Appl. Phys}. \textbf{112}, 049912-7.\\[0pt] [7] Solis, K. J., Martin, J. E., (2013) \textit{Soft Matter} \textbf{9}, 9182-9188.\\[0pt] [8] Martin, J. E., Solis, K. J., (2014) \textit{Soft Matter} \textbf{10}, 3993 (2014). [Preview Abstract] |
Wednesday, March 4, 2015 3:06PM - 3:42PM |
Q18.00002: Suppressing turbulence and enhancing the liquid suspension flows in pipelines with electrorheology Invited Speaker: Rongjia Tao Flows through pipes, such as crude oil through pipeline, are the most common and important transportation of fluids. To enhance the flow output along the pipeline requires reducing viscosity and suppressing turbulence simultaneously and effectively. Unfortunately, no method is currently available to accomplish both goals simultaneously. The talk will show that electrorheology (ER) provides an efficient solution. When a strong electric field is applied along the flow direction in a small section of pipeline, the field polarizes and aggregates the particles suspended inside the base liquid into short chains along the flow direction. Such aggregation breaks the rotational symmetry and makes the fluid viscosity anisotropic. Along the flow direction, the viscosity is significantly reduced; thus the flow along the pipeline is enhanced. In the directions perpendicular to the flow, the viscosity is substantially increased, effectively suppressing the turbulence. Recent field tests with crude oil pipeline have confirmed that this new technology works very well. For untreated crude oil, the flow inside the pipeline is turbulent as the Reynolds number exceeds 2300. However, for ER treated oil, the flow remains laminar even when the Reynolds number reaches 6000. The combination of the viscosity reduction along the flow direction and the turbulence suppression greatly saves the energy required to transport crude oil. In addition, both effects have found lasting more than 11 hours inside the pipeline after one ER treatment. No additive is needed. The process is repeatable. As turbulence is classified as one of the most important unsolved classical physics, this development is not only important for technology applications, but significant for basic physics as well. [Preview Abstract] |
Wednesday, March 4, 2015 3:42PM - 4:18PM |
Q18.00003: ER fluid in microfluid Systems Invited Speaker: Weijia Wen Electrorheological (ER) fluid is considered as a kind of smart material which is able to be used for microfluidic systems to achieve active and precise control of fluid by electrical signal. While, microfluidics, especially droplet microfluidic, attracts much attention recently from diverse research fields due to its highly integration, digitalization and computercontrolled characteristics. Here, we will introduce our recent experimental results of ER fluid-based microfluidic droplet generation and manipulation. Two methodologies by employing ER fluid into microfluidic system: digital generation, manipulation of ``smart droplets'' and droplet manipulation by ER fluid will be presented. Once it is combined with real-time detection, electroreologically integrated chip with many functions can be realized. Some other applications of using GER fluid in microfluidic chips, such as the microfluidic logical gates, are also introduced. Some potential application of ER fluid for hydraulic system will be also introduced. [Preview Abstract] |
Wednesday, March 4, 2015 4:18PM - 4:54PM |
Q18.00004: Magnetorheological fluids in occupant protection systems Invited Speaker: Norman Wereley |
Wednesday, March 4, 2015 4:54PM - 5:30PM |
Q18.00005: MR effect enhancement of bidisperse MR fluids containing micron- and nano-sized iron particles Invited Speaker: Masami Nakano Magnetorheological (MR) fluids are suspensions of micron-sized magnetic particles dispersed into carrier oils, and behave like a Bingham fluid having magnetic-field responsive yield stress. In this research, bidisperse MR suspensions containing micron- (6.6 mm) and nano- (110nm) sized spherical iron particles into silicone oil were fabricated to enhance the MR effects. The steady and dynamic MR properties have been investigated in close relation to the magnetic-induced particle cluster structure and the visualized shear flow behaviors. The static and dynamic behaviors of the particle cluster structures formed in the MR fluids under applied magnetic fields were directly visualized using an optical microscope. And the steady and dynamic MR properties of the bidisperse MR fluids~were measured using a magnetic field applicable parallel-disk rheometer.~ The MR effects of the bidisperse MR fluids changed significantly as a function of the solid fraction of nano-particles. Interestingly, field-induced shear stress was remarkably enhanced at higher shear rate when the solid fraction of nano-particles was around 25{\%}. The enhancement of the shear stress can be attributed to the formation of distinct and wide particle cluster chains. [Preview Abstract] |
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