Abstract

A novel technique is introduced for the measurement of rise velocities of hot, laminar flames. The new technique is straightforward to implement, rapid to employ, and more accurate than previous methods based on the observation of moving heated particles. In the method, tiny individual droplets of a solution containing alkali or alkaline earth elements are repetitively introduced into the flame to be examined. The small cloud of atomic vapor which is produced upon atomization of a droplet is then monitored photo-metrically as it passes two well-defined points in the flame. Knowledge of the distance between the points and measurement of the time required for the atoms to traverse it thus enables the flame velocity to be calculated. Conveniently, velocity measurements with this technique are localized in the flame, thereby permitting spatial variations in flame velocity to be examined. Moreover, the negligible mass of the moving, measured atom cloud eliminates error otherwise caused by gravitational attraction and its decelerating effect. The utility of this new technique is demonstrated through the measurement of localized velocities in a laminar, air-acetylene flame.

Application of photothermal deflection technique to flow-velocity measurements in a flame

A. Rose and R. Gupta
Opt. Lett. 10(11) 532-534 (1985)

Tunable diode-laser measurement of carbon monoxide concentration and temperature in a laminar methane–air diffusion flame

J. Houston Miller, Salma Elreedy, Bijan Ahvazi, F. Woldu, and P. Hassanzadeh
Appl. Opt. 32(30) 6082-6089 (1993)

Measurements of hydroxyl concentrations and lifetimes in laminar flames using picosecond time-resolved laser-induced fluorescence

Thomas A. Reichardt, Michael S. Klassen, Galen B. King, and Normand M. Laurendeau
Appl. Opt. 35(12) 2125-2139 (1996)

Temperature measurements of the hydroxyl radical and molecular nitrogen in premixed, laminar flames by laser techniques

J. H. Bechtel
Appl. Opt. 18(13) 2100-2106 (1979)

Giant-pulsed laser Raman oxygen measurements in a premixed laminar methane–air flame

Jürgen Haumann and Alfred Leipertz
Appl. Opt. 24(24) 4509-4515 (1985)