Ferrohydrodynamic flows in uniform and non-uniform rotating magnetic fields
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2008
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| Online Access: | http://dspace.mit.edu/handle/1721.1/38574 http://hdl.handle.net/1721.1/38574 |
| _version_ | 1811085299140263936 |
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| author | He, Xiaowei, Ph. D. Massachusetts Institute of Technology |
| author2 | Markus Zahn. |
| author_facet | Markus Zahn. He, Xiaowei, Ph. D. Massachusetts Institute of Technology |
| author_sort | He, Xiaowei, Ph. D. Massachusetts Institute of Technology |
| collection | MIT |
| description | Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006. |
| first_indexed | 2024-09-23T13:06:45Z |
| format | Thesis |
| id | mit-1721.1/38574 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T13:06:45Z |
| publishDate | 2008 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/385742019-04-12T08:53:05Z Ferrohydrodynamic flows in uniform and non-uniform rotating magnetic fields He, Xiaowei, Ph. D. Massachusetts Institute of Technology Markus Zahn. Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. Electrical Engineering and Computer Science. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006. Includes bibliographical references (p. 233-241). Ferrofluids are conventionally used in such DC magnetic field applications as rotary and exclusion seals, stepper motor dampers, and heat transfer fluids. Recent research demonstrates ferrofluid use in alternating and rotating magnetic fields for MEMS/NEMS application of microfluidic devices and bio-applications such as targeted drug delivery, enhanced Magnetic Resonance Imaging, and hypothermia. This thesis studies ferrofluid ferrohydrodynamics in uniform and non-uniform rotating magnetic fields through modeling and measurements of ferrofluid torque and spin-up flow profiles. To characterize the water-based and oil-based ferrofluids used in the experiments, measurements were made of the mass density, surface tension, viscosity, magnetization curve, nanoparticle size, and the speed of sound. Initial analysis for planar Couette and Poiseuille flows exploit DC magnetic field effects on flow and spin velocities with zero spin viscosity. Above critical values of magnetic field strength and flow velocity, multiple values of magnetic field, spin velocity, and effective magnetoviscosity result, indicating that zero spin viscosity may be non-physical. Torque and spin-up flow profile measurements show the effect of volume torque density and body force density in uniform and non-uniform rotating magnetic fields. (cont.) Ferrofluid "negative viscosity" measurements in uniform and non-uniform rotating magnetic fields occur when magnetic field induced flow creates torque that exceeds the torque necessary to drive a viscometer spindle. Numerical simulations of torque and spin-up flow in uniform and non-uniform rotating magnetic fields, including contribution from the spin velocity and spin viscosity terms, are fitted to measurements to estimate the value ranges of relaxation time r - 1.3-30 gs and spin viscosity n' - 1-11.8x109 Nos in waterbased ferrofluid. Based on the ferrohydrodynamic theory and models, theory of the complex magnetic susceptibility tensor is derived, which depends on spin velocity, that can be a key to external magnetic field control of ferrofluid biomedical applications. Preliminary impedance analysis and measurements investigate complex magnetic susceptibility change of ferrofluid in oscillating and rotating uniform magnetic fields and allow calculation of the resulting dissipated power or mechanical work in pumping fluid. by Xiaowei He. Ph.D. 2008-01-10T17:22:48Z 2008-01-10T17:22:48Z 2006 2006 Thesis http://dspace.mit.edu/handle/1721.1/38574 http://hdl.handle.net/1721.1/38574 155855004 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/38574 http://dspace.mit.edu/handle/1721.1/7582 241, A1-A26 p. application/pdf Massachusetts Institute of Technology |
| spellingShingle | Electrical Engineering and Computer Science. He, Xiaowei, Ph. D. Massachusetts Institute of Technology Ferrohydrodynamic flows in uniform and non-uniform rotating magnetic fields |
| title | Ferrohydrodynamic flows in uniform and non-uniform rotating magnetic fields |
| title_full | Ferrohydrodynamic flows in uniform and non-uniform rotating magnetic fields |
| title_fullStr | Ferrohydrodynamic flows in uniform and non-uniform rotating magnetic fields |
| title_full_unstemmed | Ferrohydrodynamic flows in uniform and non-uniform rotating magnetic fields |
| title_short | Ferrohydrodynamic flows in uniform and non-uniform rotating magnetic fields |
| title_sort | ferrohydrodynamic flows in uniform and non uniform rotating magnetic fields |
| topic | Electrical Engineering and Computer Science. |
| url | http://dspace.mit.edu/handle/1721.1/38574 http://hdl.handle.net/1721.1/38574 |
| work_keys_str_mv | AT hexiaoweiphdmassachusettsinstituteoftechnology ferrohydrodynamicflowsinuniformandnonuniformrotatingmagneticfields |