Chirped-Probe-Pulse Femtosecond Coherent Anti-Stokes Raman Scattering Thermometry Mapping in Turbulent Flames

Femtosecond chirped-probe-pulse (CPP) CARS technology has become a powerful tool for measuring complex high-temperature combustion temperatures due to its interference-free characteristics, high accuracy, and excellent time resolution. The experiment uses a specific energy-matching method to effectively separate the signal light from the background light and thus improve the accuracy of the measurement. The optimization was confirmed in the inner and outer flames of the butane Bunsen burner, with the best accuracy of 3.2% and 1.7% at 1385 and 1411 K, respectively. The two-dimensional temperature distribution at the outlet of the heat gun was experimentally measured using the aforementioned energy-matching method. The results show that the average accuracy can be below 2% at temperatures exceeding 700 K and that the temperature distribution corresponds to the nozzle structure at the air outlet. The experimental results demonstrate the successful acquisition of spatially resolved 2D temperature distributions under challenging high-temperature turbulent combustion conditions using femtosecond CPP CARS, providing valuable reference data for turbulent combustion studies.