Quantitative 2D thermometry in turbulent sooting non-premixed flames using filtered Rayleigh scattering

Area of Science:

• Combustion science
• Laser-based diagnostics
• Thermometry

Background:

• Accurate temperature measurement is crucial for understanding turbulent sooting flames.
• Existing methods face challenges in complex flame environments, particularly with soot interference.

Purpose of the Study:

• To develop and validate a novel thermometry method for turbulent sooting non-premixed flames.
• To achieve accurate, high-resolution 2D temperature measurements across the full range of mixture fractions.
• To demonstrate the robustness of the method in the presence of soot.

Main Methods:

• Utilized fuel tailoring with a specific C2H2-based mixture for consistent Rayleigh scattering cross-section.
• Employed filtered Rayleigh scattering (FRS) for single-shot thermometry.
• Evaluated accuracy and precision in various flame configurations, including laminar and turbulent sooting flames.
• Compared FRS results with laser Rayleigh scattering (LRS) in non-sooting regions.

Main Results:

• Achieved high single-shot measurement precision (SNR 65-80) for temperatures between 1900-2200 K.
• Demonstrated excellent agreement between FRS thermometry and LRS in non-sooting conditions.
• Showed no interference from soot particles with the FRS-based approach.
• Obtained high SNR (60-74) 2D temperature imaging in turbulent sooting flames.

Conclusions:

• The proposed FRS thermometry method is accurate and precise for turbulent sooting flames.
• The fuel tailoring approach enables reliable temperature determination across all mixture fractions.
• This technique offers a robust, high-resolution 2D temperature measurement solution for challenging combustion environments.