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Aspects of cool-flame supported droplet combustion in microgravity
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Nayagam, Vedha Williams, Forman A. Dietrich, Daniel L. |
| Copyright Year | 2015 |
| Description | Droplet combustion experiments performed on board the International Space Station have shown that normal-alkane fuels with negative temperature coefficient (NTC) chemistry can support quasi-steady, low-temperature combustion without any visible flame. Here we review the results for n-decane, n-heptane, and n-octane droplets burning in carbon dioxidehelium diluted environments at different pressures and initial droplet sizes. Experimental results for cool-flame burning rates, flame standoff ratios, and extinction diameters are compared against simplified theoretical models of the phenomenon. A simplified quasi-steady model based on the partial-burning regime of Lin predicts the burning rate, and flame standoff ratio reasonably well for all three normal alkanes. The second-stage cool-flame burning and extinction following the first-stage hot-flame combustion, however, shows a small dependence on the initial droplet size, thus deviating from the quasi-steady results. An asymptotic model that estimates the oxygen depletion by the hot flame and its influence on cool-flame burning rates is shown to correct the quasi-steady results and provide a better comparison with the measured burning-rate results.This work was supported by the NASA Space Life and Physical Sciences Research and Applications Program and the International Space Station Program. |
| File Size | 1412488 |
| Page Count | 20 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20160000344 |
| Archival Resource Key | ark:/13960/t88h3mv9s |
| Language | English |
| Publisher Date | 2015-11-11 |
| Access Restriction | Open |
| Subject Keyword | Cool Flames Microgravity Drops (liquids) Oxygen Heptanes Extinction Flame Temperature Alkanes Combustion Quasi-steady States Drop Size Drops Liquids International Space Station Hydrocarbon Fuels Burning Rate Low Temperature Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Presentation |
