Simple calibrated nonlinear excitation regime two-line atomic fluorescence thermometry

Area of Science:

• Combustion diagnostics
• Optical thermometry
• Laser spectroscopy

Background:

• Nonlinear excitation regime two-line atomic fluorescence (NTLAF) is a 2D thermometry technique for turbulent sooty flames.
• Current NTLAF methods face challenges due to complex calibration and expensive instrumentation.

Purpose of the Study:

• To develop a simplified and cost-effective NTLAF measurement approach.
• To reduce the number of system parameters requiring calibration in NTLAF.

Main Methods:

• A one-parameter NTLAF model was developed.
• Tunable diode laser absorption spectroscopy (TDLAS) was used for calibration.
• Path-averaged temperature from TDLAS calibrated a single system parameter.

Main Results:

• Instantaneous 2D thermometry data were acquired for a homemade burner.
• Measurement uncertainty was approximately 4.5%.
• Results showed deviations less than 50 K (typically within 20 K) from TDLAS and Rayleigh scattering measurements.

Conclusions:

• The proposed method offers a simplified NTLAF solution for noncontact, in-situ, high-resolution 2D temperature measurement.
• This approach is expected to improve NTLAF's compatibility in research and engineering applications.