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Measurement of Transient 2-D Profiles of Velocity and Fuel-Concentration Over Liquids.


pdf icon Measurement of Transient 2-D Profiles of Velocity and Fuel-Concentration Over Liquids. (1401 K)
Ito, A.; Narumi, A.; Konishi, T.; Tashtoush, G.; Saito, K.; Cremers, C. J.

NIST GCR 96-704; 24 p. December 1996.

Sponsor:

National Institute of Standards and Technology, Gaithersburg, MD

Available from:

National Technical Information Service
Order number: PB97-137574

Keywords:

pool fires; velocity; temperature; flame spread

Abstract:

We recently developed two different optical techniques in order to simultaneously measure transiet 2-D profiles of velocity, temperature and fuel concentration which were generated by a spreading flame over liquids. The first technique, PTLS employs a particle-track system combined with a laser-sheet system and a high speed camera, while the second technique employs a dual wavelength holographic interferometer (DWHI). The PTLS system revealed transient 2 D profiles of flame incuded flow, while DWHI revealed 2 D profiles of fuel concentration over liquids. In this paper we present a series of velocity profiles for a pulsating flame spread over propanol and concentration profiles for gaseous propanol determined with PTLS and DWHI respectively. Other researchers have predicted the formation of small twin circulations, one a gas-phase circulation just ahead of the flame's leading edge, and the other a small liquid circulation just underneath the gas-phase circulation. Our PTLS results confired these predictions, i.e., the formation of a millimeter-diameter circulation in the gas phase and an accompanying liquid flow. Based on these data, we offer a phenomenological explanation of the mechanism of pulsating flame spread. In addition, we show that DWHI is a very promising technique for measuring transient fuel-concentration profiles over liquids.