A. James Clark School of Engineering

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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

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    SMOKE POINTS OF MICROGRAVITY AND NORMAL GRAVITY COFLOW DIFFUSION FLAMES
    (2009) Dotson, Keenan Thomas; Sunderland, Peter B; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Smoke points were measured in microgravity aboard the International Space Station (ISS) as part of the Smoke Points in Coflow Experiment (SPICE), and in normal gravity conditions. In microgravity conditions increasing the coflow velocity or decreasing the burner diameter increased the smoke point flame length. A simplified prediction of centerline jet velocity did not yield residence-time-based criticalities or data collapse. Simulation of non-reacting flows showed that the simplified centerline velocity prediction was able to predict velocity decay for only relatively weak coflows. An improved model may yield different results. In normal earth gravity coflow velocity exhibited mixed effects. For burner diameters of 0.41, 0.76, and 1.6 mm, smoke points increased with increases of coflow velocity. For an unconfined coflow burner with a burner diameter of 13.7 mm smoke point length decreased with increasing coflow velocity for ethylene and propylene, while increasing for propane flames.
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    Thin-Filament Pyrometry with a Digital Still Camera
    (2006-05-08) Maun, Jignesh D; Sunderland, Peter B; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    A novel thin-filament pyrometer is presented here. It involves a consumer-grade color digital still camera with a charged-couple device sensor with 3008 X 2000 pixels and 12 bits per color plane. A blue Schott filter and custom white balance were used to yield similar red, green and blue intensities along the fibers. SiCO fibers with diameters of 13.9 microns were used and scanning-electron microscopy revealed the fibers to be uniform. Measurements were performed in a methane/air coflowing laminar jet diffusion flame with a luminosity length of 72 mm. Calibration of the pyrometer was accomplished with B-type thermocouple measurements. The camera was found to be well suited to thin-filament pyrometry. The pyrometry measurements yielded gas temperatures in the range of 1350 - 2200 K with an estimated uncertainty of ± 60 K, a relative temperature resolution of ± 0.215 K, a spatial resolution of 42 µm and a temporal resolution of 0.66 ms. Fiber aging had no effect on the results. Soot deposition was less problematic for the pyrometer than for the thermocouple.