Rapid Three-Dimensional Flame Temperature Reconstruction Using Mid-Infrared Dual-Comb Spectroscopy

Accurate, rapid, and multidimensional temperature diagnostics are essential for understanding and controlling combustion processes under extreme conditions. Unlike conventional techniques that often require complex multi-detector configurations, we present a single-detector method for three-dimensional (3D) flame temperature reconstruction based on mid-infrared dual-comb spectroscopy. By employing frequency-domain spectral encoding, the system simplifies implementation while enhancing stability and spatiotemporal resolution. This method integrates laser-spectrum optimization and time-division multiplexing, eliminating the need for detector arrays and synchronization. Simulations and experiments confirmed that an acquisition time of ~ 9 ms provides sufficient accuracy (SNR ≈ 20, error < 4%), whereas sub-ms acquisition reduces the SNR to ~ 6 and increases errors to ~ 10%. Guided by this finding, we achieved high-precision 3D temperature reconstruction of flames fields and determined the dynamic evolution of acoustically perturbed combustion with a temporal resolution of 9 ms, highlighting the potential of this high-resolution, multi-line absorption approach for rapid combustion-field diagnostics. This work demonstrates the ability of this technology to obtain full-field, high-spatiotemporal-resolution measurements, offering new opportunities for investigating transient phenomena and optimizing combustion systems.