Abstract:
This paper presents the results of experimental panoramic measurements of the temperature field by a method based on the registration of laser-induced fluorescence of the hydroxyl radical $(\mathrm{OH})$ upon excitation of two different transitions (two-line PLIF) in a laminar conical flame of a gas-droplet mixture of ethyl alcohol and air. Laminar flow of the uniformly mixed ethyl alcohol/air mixture with fine droplets is produced by an ultrasonic atomizer inside the liquid ethanol tank. The properties of the two-phase flow at the nozzle outlet without combustion was controlled by a time-of-flight optical sensor. The temperature field was estimated based on the excitation of the $Q_1(5)$ and
$Q_1(14)$ lines of the $(1-0)$ transition of the $A^2\Sigma^+ -X^2\Pi$ electronic system. The spatial unevenness of the energy distribution in the laser knife illuminating the central plane of the flame cone and the change in the pulse energy from frame to frame were compensated by the use of an additional camera recording the laser radiation intensity distribution in the calibration cuvette.
Keywords:laminar flame, ethanol combustion, combustion of gas-droplet mixture and air, OH PLIF, panoramic thermometry two-line OH PLIF.
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