Measurement of hydroxyl concentration of transient premixed methane-air flames by planar laser induced fluorescence (PLIF) method.

摘要

Northeastern University has established a new Planar Laser Induced Fluorescence system for studying transient high temperature flames in constant volume combustion vessels. This system includes a tunable laser system, charge-coupled device camera, combustion vessel, and a computer used for experiment operation, data acquisition, and data analysis. A timing system was developed which coordinates the pulsing laser beam, combustion ignition, and image acquisition with high precision so that flames of a desired radii could be imaged.;The timing system was proven using different fuel to air concentrations of methane-mixtures with initial room temperature and atmospheric pressure. Snapshots of each mixture's OH concentration were taken at a similar flame radius. All images were processed with calibration data which corrected for background offset, laser pulse energy fluctuation, uneven energy distribution in the laser sheet, and image distortion. This work has laid the groundwork for further experiments which will establish a database of experimental data which can be used to validate chemical kinetics mechanisms.