The effect of a non-uniform magnetic field on the coupled transport of
momentum and heat is studied for the case of laminar pipe flow of a
magnetically susceptible ferrofluid. The momentum and heat transport
equations are complemented with the necessary electromagnetic terms and
used to develop a computer simulation of the velocity profile and temperature
distribution in the fluid.
Two magnetic field configurations are studied. The first configuration is
produced by a single short solenoid, located around the pipe. The magnetic
field produced has both radial and axial components. For the second
configuration, the electric current is inverted in one half of the solenoid,
creating much stronger field gradients in both directions.
The flow is laminar, driven by a constant pressure difference between
the ends of the pipe. The apparent viscosity of the ferrofluid is modeled as
dependent on temperature and magnetic field. In simulations involving heat
transfer, a section of the pipe is maintained at higher constant temperature.
The rest of the wall is adiabatic.
A Visual-Basic code, FiRMa (Flow in Response to Magnetic field), was
developed to perform the numerical simulations.
For the water-based ferrofluid, results show reduction of average
velocity and small deviations from the parabolic velocity profile as the result of
vortex viscosity. Heat transfer calculations show a decrease in the heat
transfer coefficient and an increase in the fluid exit temperature. These effects
are due to the change in flow pattern and average velocity.
Current research aims for the development of a stable liquid-metal
based ferrofluid, because of the high electric and thermal conductivities. The
FiRMa code is used to examine the expected response of a mercury-based
ferrofluid to the magnetic fields under study. Results show that the
electromagnetic effects on the liquid metal-based ferrofluid are much stronger,
due to induced electric currents and the Lorentz force acting on them. / Graduation date: 2003
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/31656 |
| Date | 02 April 2003 |
| Creators | Cruz-Fierro, Carlos Francisco |
| Contributors | Jovanovic, Goran N. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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