Structure and Soot Properties of Nonbuoyant Ethylene/Air Laminar Jet Diffusion Flames.
Structure and Soot Properties of Nonbuoyant Ethylene/Air
Laminar Jet Diffusion Flames.
Urban, D. L.; Yuan, Z. G.; Sunderland, P. B.; Linteris,
G. T.; Voss, J. E.; Lin, K. C.; Dai, Z.; Sun, K.; Faeth,
AIAA Journal, Vol. 36, No. 8, 1346-1360, August 1998.
soot; jet flames; diffusion flames; flame structure;
experiments; space shuttle; microgravity
The structure and soot properties of round,
soot-emitting, nonbuoyant, laminar jet diffusion flames
are described, based on long-duration (175-230-s)
experiments at microgravity carried out on orbit in the
Space Shuttle Columbia. Experimental conditions
included ethylene-fueled flames burning in still air at
nominal pressures of 50 and 100 kPa and an ambient
temperature of 300 K with luminous flame lengths of
49-64 mm. Measurements included luminous flame shapes
using color video imaging, soot concentration (volume
fraction) distributions using deconvoluted laser
extinction imaging, soot temperature distributions using
deconvoluted multiline emission imaging, gas temperature
distributions at fuel-lean (plume) conditions using
thermocouple probes, soot structure distributions using
thermophoretic sampling and analysis by transmission
electron microscopy, and flame radiation using a
radiometer. The present flames were larger, and emitted
soot more readily, than comparable flames observed
during ground-based microgravity experiments due to
closer approach to steady conditions resulting from the
longer test times and the reduced gravitational
disturbances of the space-based experiments.