Abstract
In order to better understand the combustion behavior of spray flames, simultaneous measurements of droplet cluster visualization using laser tomography and local OH chemiluminescence and CH-band emission using a newly developed optical probe system named the Multi-color Integrated Cassegrain Receiving Optics (MICRO) are applied to a premixed-spray flame. Time-series planar images of droplet clusters and their transient structures during combustion are examined using an Ar-ion laser and a high-speed digital CCD camera. By observing the droplet clusters and local chemiluminescence simultaneously in the premixed- spray flame, it is confirmed that some portions of the spray stream disappear very rapidly due to preferential flame propagation, while other portions of the spray stream survive over a long period to form droplet clusters, disappearing gradually from their outermost portions, which seems similar to a diffusion flame. The disappearance speed of individual droplet clusters in the premixed-spray flame, instead of a conventional evaporation rate of a single droplet, is defined and calculated by processing the obtained droplet-cluster planar images. The disappearance speed for rapid preferential flame propagation through easy-to-burn regions in the upstream region of the flame is about 2.5 m/s. On the other hand, the disappearance speed when droplet clusters burn dominated by a diffusion combustion mode in the downstream region of the flame is approximately 0.45 m/s.
Original language | English |
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Pages (from-to) | 1967-1974 |
Number of pages | 8 |
Journal | Symposium (International) on Combustion |
Volume | 27 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1998 |
Externally published | Yes |
Event | 27th International Symposium on Combustion - Boulder, CO, United States Duration: 1998 Aug 2 → 1998 Aug 7 |
ASJC Scopus subject areas
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology
- Mechanical Engineering
- Physical and Theoretical Chemistry
- Fluid Flow and Transfer Processes