Single-camera, single-shot, time-resolved laser-induced incandescence decay imaging

Area of Science:

• Combustion science
• Laser-based diagnostics
• Particle characterization

Background:

• Soot particle size is crucial for understanding combustion processes and heat transfer.
• Current time-resolved laser-induced incandescence (TiRe-LII) methods for planar measurements are complex, requiring multiple cameras or laser pulses.
• These limitations hinder application in unsteady or turbulent combustion environments.

Purpose of the Study:

• To develop and validate a simplified technique for planar soot particle sizing using TiRe-LII.
• To enable measurements in challenging combustion conditions, including turbulent flames.
• To advance the understanding of soot formation and its impact on combustion.

Main Methods:

• Utilized a single high-sensitivity, ultra-high-speed 10 MHz camera with a 50 ns gate and no intensifier.
• Acquired background flame luminosity, prompt LII, and TiRe-LII decay signals within a single laser shot.
• Validated the technique in a laminar non-premixed ethylene flame before application to a turbulent ethylene jet flame.

Main Results:

• Successfully demonstrated planar soot particle sizing using a single-shot, intensified-free TiRe-LII approach.
• Obtained measurements of flame luminosity, prompt LII, and TiRe-LII decay signals.
• Validated the technique's efficacy in both laminar and turbulent ethylene flames.

Conclusions:

• The developed single-camera, single-shot TiRe-LII technique offers a simplified and effective method for planar soot particle sizing.
• This advancement facilitates measurements in complex and unsteady combustion environments, such as turbulent flames.
• The technique provides valuable data for soot formation studies and combustion optimization.