- Author
-
Wherley, B. L.
|
Strehlow, R. A.
- Title
- Behavior of Fuel-Lean Premixed Flames in a Standard Flammability Limit Tube Under Controlled Gravity Conditions. Final Report. January 1985-December 1985.
- Coporate
- Illinois Univ. at Urbana-Champaign
- Report
-
NASA CR-177132; NASA NCC 3-35; UILU ENG 86-0503,
July 1986,
143 p.
- Distribution
- Available from National Technical Information Service
- Keywords
-
premixed flames
|
flammability limits
|
gravity
|
weightlessness
|
research facilities
- Identifiers
- zero gravity
- Abstract
- Fuel-lean flames in methane-air mixtures from 4.90 to 6.20 volume percent fuel and propane-air mixtures from 1.90 to 3.00 volume percent fuel were studied in the vicinity of the limit for a variety of gravity conditions. The limits were determined and the behavior of the flames studied for one-g upward, one-g downward, and zero-g propagation. The one-g upward and downward propagating flames were observed in ground tests which zero-g was achieved in the NASA Lewis Airborne Research Facility, a modified Lear jet Model 25, by flying along Keplerian trajectories. This provided approximately 20 seconds of zero-g. Gravity conditions also were varied in constant increments from 0.0 to 2.0 g's for upward propagation and continuously from 0.0 to 2.0 g's for upward and downward propagation. The flammability limit apparatus was designed to fit into two standardized aluminum racks, one containing a carrousel of eight shortened (0.71) meter SFLT's. These were filled on the ground with mixtures of methane or propane and air and ignited at the open end of the tube in flight under the desired gravity conditions. Photographic data were collected using two 16 mm movie cameras mounted in the other rack, which also contained an automatic sequencing system to properly synchronize starting the cameras, opening of the tube, firing of the igniter, and, finally, to shut down all equipment when the experiment had been completed.