Clarification of the flame structure of droplet burning based on temperature measurement in microgravity
- Univ. of Tokyo (Japan)
- Ishikawajima-Harima Heavy Industries Co., Ltd., Tokyo (Japan)
In microgravity, soot accumulates inside the flame in droplet combustion. The yellow luminosity prevents the inner structure of the flame from being revealed. No experimental work has been conducted on the flame structure of the droplet burning in microgravity. Microgravity experiments on the droplet burning were performed for the purpose of clarifying the flame structure of spherically symmetrical burning of the droplet by using the drop tower. Gas temperature was measured by thermocouples with tip parts that are concentric with the spherical flame. This configuration reduces heat loss from the contact point of the thermocouple to the supporting wires. The gas-temperature distributions and temporal variations of the flame temperature were obtained and were examined for an ambient pressure ranging from 0.1 to 1.1 MPa. It was found that the maximum temperature zone, that is, the primary reaction zone, exists about 0.8 mm outside the outer edge of the yellow luminous zone at 0.1 MPa for n-heptane droplets. The distance between the reaction zone and the enter edge of the yellow luminous zone decreases with increasing ambient pressure. The flame temperature is almost constant at the normalized time ranging from 0.3 to 0.6 and less dependent on the ambient pressure, than on oxygen concentration of the ambient gas. In the later period of combustion, the flame temperature decreases with time because of the increase in the soot accumulation.
- OSTI ID:
- 93191
- Report Number(s):
- CONF-940711--
- Country of Publication:
- United States
- Language:
- English
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