This experiment is concerned with sampling submicrometer
particles in near sonic and supersonic flows.
The study employed a high volume condensation aerosol
generator to produce stearic acid particles having a
geometric mean diameter of 0.8 μm and a geometric
standard deviation of 1.28. The aerosol was diluted
with dry air and accelerated to Mach 0.6, 0.8, 1.26, or
1.47 through a flow nozzle. Aerosol mass concentrations
were determined using a small bore probe in the
jet and by a large bore probe sampling isokinetically
upstream of the jet nozzle. The results of both
samples were compared to compute the sampling error
associated with the high speed jet sample. The mass of
stearic acid collected on polycarbonate membrane
filters was determined by gravimetric and chromatographic
methods. Studies at Mach 0.8 with four
sampling probes having inlet wall to bore area ratios
ranging from 3.8 to 0.28 demonstrated that probe wall
thickness effects are not significant when the sample
is extracted isokinetically. Subisokinetic experiments
using a knife edged probe showed relative errors of
124 ± 12% when sampling at 20% of the isokinetic
condition. The subisokinetic results are compared
favorably with the extended empirical results of other
authors. For the supersonic cases it is shown that the
subsonic velocity downstream of the sampling probe bow
shock can be used in estimating the sampling error. / Graduation date: 1991
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37476 |
| Date | 06 July 1990 |
| Creators | Martone, Joseph Arthur |
| Contributors | Boubel, Richard W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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