Effects of properties of atmosphere diluents on cool-flame combustion of normal-alkane droplets
| Autor: | Vedha Nayagam, Forman A. Williams, Daniel L. Dietrich |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Alkane
chemistry.chemical_classification Materials science 010304 chemical physics General Chemical Engineering General Physics and Astronomy Energy Engineering and Power Technology chemistry.chemical_element Thermodynamics 02 engineering and technology General Chemistry Cool flame Combustion 01 natural sciences Diluent chemistry.chemical_compound Fuel Technology Xenon 020401 chemical engineering chemistry Extinction (optical mineralogy) 0103 physical sciences Carbon dioxide 0204 chemical engineering Helium |
| Zdroj: | Combustion and Flame. 229:111408 |
| ISSN: | 0010-2180 |
| DOI: | 10.1016/j.combustflame.2021.111408 |
| Popis: | Droplet combustion experiments carried out in the International Space Station using n-alkane fuels have shown that large droplets, when ignited, first burn with visible hot flames and then extinguish, only to be followed later by quasi-steady cool-flame combustion. In a few of these experiments, some of the nitrogen in the nitrogen-oxygen ambient-gas mixture was replaced by helium, carbon dioxide, or xenon, for n-heptane, n-octane, n-decane, or n-dodecane droplets. Different diluents were observed to exert remarkably different influences on the cool-flame combustion. These initially unexpected differences are summarized here, with explanations offered for their causes. In particular, a simplified theoretical description of cool-flame-supported droplet combustion is employed to predict burning-rate constants and droplet diameters at cool-flame extinction, resulting in good agreement with much of the experimental data but disagreement with certain measurements, for reasons that are explained. The comparisons underscore the important influence of the diluent, especially on the Lewis numbers of cool-flame intermediate species derived from the fuel vapor. |
| Databáze: | OpenAIRE |
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