Single-pulse laser-induced OH fluorescence in an atmospheric flame, spatially resolved with a diode array detector

Area of Science:

• Combustion science
• Laser diagnostics
• Chemical kinetics

Background:

• Hydroxyl radical (OH) is a key intermediate in combustion processes.
• Understanding OH distribution is crucial for modeling flame behavior and pollutant formation.
• Soot formation in hydrocarbon flames impacts air quality and energy efficiency.

Purpose of the Study:

• To measure OH radical distributions in different flame types.
• To demonstrate the capability of laser-induced fluorescence for high-resolution flame analysis.
• To provide data for validating combustion models.

Main Methods:

• Laser-induced fluorescence (LIF) measurements using a single 6-nsec pulse.
• Utilized a frequency-doubled dye laser pumped by a Nd:YAG laser.
• Achieved ~25 micrometer spatial resolution by imaging onto a gated, intensified diode array.

Main Results:

• OH fluorescence was successfully measured in both stoichiometric CH(4)/air and sooting propane flames.
• High spatial resolution allowed detailed mapping of OH radical distributions.
• Data provides insights into OH radical behavior in relation to flame stoichiometry and soot.

Conclusions:

• Laser-induced fluorescence is a powerful tool for spatially resolved OH measurements in flames.
• The study provides valuable experimental data for combustion research.
• Findings contribute to a better understanding of flame chemistry and soot formation mechanisms.