Development of a picosecond lidar system for large-scale combustion diagnostics

Area of Science:

• Combustion diagnostics
• Laser-based sensing technologies
• Optical measurement techniques

Background:

• Limited optical access in full-scale combustion devices like power plants poses challenges for diagnostics.
• Existing methods may lack the resolution or single-shot capability required for dynamic combustion analysis.
• Accurate temperature and species measurements are crucial for optimizing combustion efficiency and reducing emissions.

Purpose of the Study:

• To develop and demonstrate a picosecond lidar system for single-ended combustion diagnostics.
• To evaluate the system's capability for high-resolution temperature measurements (Rayleigh thermometry) and soot mapping.
• To explore the potential of differential absorption lidar for fuel visualization.

Main Methods:

• Development of a picosecond lidar system with a range resolution of less than 0.5 cm.
• Demonstration in Bunsen burner flames (sooty and non-sooty) and a McKenna burner with an ethylene flame.
• Application of Rayleigh thermometry for temperature measurements across various equivalence ratios.
• Investigation of differential absorption lidar for acetone vapor jet visualization.

Main Results:

• The picosecond lidar system achieved a range resolution of <0.5 cm.
• Successful single-shot Rayleigh thermometry was demonstrated, showing potential for 2D measurements.
• Qualitative mapping of soot occurrence was found to be possible.
• Differential absorption lidar proved effective for fuel visualization in acetone vapor jets.

Conclusions:

• Picosecond lidar is a promising technique for single-ended, high-resolution combustion diagnostics in challenging environments.
• The system shows potential for advanced applications like single-shot 2D thermometry and soot analysis.
• Differential absorption lidar offers a viable method for fuel visualization in combustion studies.