doi:10.3850/978-981-08-7724-8_12-04

ABSTRACT

Laminar smoke points were measured in non-buoyant laminar jet diffusion flames in coflowing air aboard the International Space Station. Fifty-two smoke points were found for ethylene, propane, propylene, and propylene/nitrogen mixtures. Burner diameters were 0.41, 0.76, and 1.6 mm and co-flow velocities varied from 5.4–65 cm/s. These flames allow extensive control over residence time via variations in dilution, burner diameter, and co-flow velocity. The measured smoke point lengths were found to correlate with burner diameter to the –0.77 power times co-flow velocity to the 0.48 power. The measurements allow estimates of pseudo threshold soot indices (TSI) for microgravity diffusion flames. A model of residence times in co-flowing flames is developed, and although residence time helps explain many of the observations, it does not correlate the measured smoke points.

Keywords: Combustion, Laminar flames, Microgravity, Soot.

© 2011 CPD Unit, University of Leeds