Instantaneous temperature field measurements using planar laser-induced fluorescence.

Area of Science:

• Combustion Science
• Laser Diagnostics
• Fluid Dynamics

Background:

• Accurate temperature measurements are crucial for understanding combustion processes.
• Existing methods may lack the spatial or temporal resolution needed for dynamic flame analysis.

Purpose of the Study:

• To develop and demonstrate a single-pulse, laser-induced fluorescence (LIF) diagnostic.
• To measure two-dimensional (2D) temperature fields in combustion flows with high temporal resolution.

Main Methods:

• Utilizes sheet illumination from a tunable laser for planar LIF.
• Employs a stable tracer molecule seeded at a constant mole fraction.
• Leverages the nitric oxide (NO) A(2) Sigma(+) ? X(2)II transition (lambda approx. 225.6 nm) for excitation.

Main Results:

• Successfully implemented a 2D temperature field measurement technique.
• Demonstrated high temporal resolution, limited by the laser pulse duration.
• Presented experimental results for a rod-stabilized, premixed methane-air flame.

Conclusions:

• The described LIF diagnostic is effective for 2D temperature mapping in combustion.
• The technique offers high temporal resolution suitable for transient combustion phenomena.
• This method provides valuable data for combustion modeling and analysis.