Numerical simulations were performed to study the turbulent mixing of a scalar
species in straight tube, single and double elbow flow configurations. Different Reynolds
Averaged Navier Stokes (RANS) and Large Eddy Simulation (LES) models were used
to model the turbulence in the flow. Conventional and dynamic Smagorinsky sub-grid
scale models were used for the LES simulations. Wall functions were used to resolve the
near wall boundary layer. These simulations were run with both two-dimensional and
three-dimensional geometries. The velocity and tracer gas concentration Coefficient of
Variations were compared with experimental results. The results from the LES
simulations compared better with experimental results than the results from the RANS
simulations. The level of mixing downstream of a S-shaped double elbow was higher
than either the single elbow or the U-shaped double elbow due to the presence of counter
rotating vortices. Penetration of neutralized and non-neutralized aerosol particles
through three different types of tubing was studied. The tubing used included standard
PVC pipes, aluminum conduit and flexible vacuum hose. Penetration through the aluminum conduit was unaffected by the presence or absence of charge neutralization,
whereas particle penetrations through the PVC pipe and the flexible hosing were
affected by the amount of particle charge. The electric field in a space enclosed by a
solid conductor is zero. Therefore charged particles within the conducting aluminum
conduit do not experience any force due to ambient electric fields, whereas the charged
particles within the non-conducting PVC pipe and flexible hose experience forces due to
the ambient electric fields. This increases the deposition of charged particles compared
to neutralized particles within the 1.5â PVC tube and 1.5â flexible hose. Deposition
2001a (McFarland et al. 2001) software was used to predict the penetration through
transport lines. The prediction from the software compared well with experiments for all
cases except when charged particles were transported through non-conducting materials.
A Stairmand cyclone was designed for filtering out large particles at the entrance of the
transport section.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4902 |
| Date | 25 April 2007 |
| Creators | Vijayaraghavan, Vishnu Karthik |
| Contributors | Hassan, Yassin A., McFarland, Andrew |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 3283324 bytes, electronic, application/pdf, born digital |
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