Mid-infrared dual-comb spectroscopy for rapid temperature distribution characterization.

Area of Science:

• Spectroscopy
• Physical Chemistry
• Optical Engineering

Background:

• Combustion systems are complex, high-temperature environments influenced by chemical reactions and phase changes.
• Accurate spatio-temporal temperature field monitoring is essential for understanding combustion processes.
• Existing methods may lack the speed or precision required for dynamic combustion analysis.

Purpose of the Study:

• To propose and validate a novel, fast, and high-precision temperature measurement technique.
• To achieve spatio-temporally resolved temperature measurements in a non-uniform temperature field.
• To demonstrate the applicability of mid-infrared dual-comb spectroscopy (DCS) for combustion diagnostics.

Main Methods:

• Utilized mid-infrared (MIR) dual-comb spectroscopy (DCS) for temperature measurement.
• Achieved high spectral resolution and a fast refresh rate for dynamic monitoring.
• Acquired bandhead ro-vibrational lines of the CO2 molecule to retrieve temperature data.

Main Results:

• Successfully performed spatio-temporally resolved temperature measurements along a laser path.
• Achieved a 1-σ temperature uncertainty of 3.2°C at 800°C within a 100 ms timeframe.
• Demonstrated the technique's capability for precise temperature retrieval in complex environments.

Conclusions:

• The proposed MIR DCS technique offers a fast and high-precision solution for temperature measurement.
• This laser diagnostic method has significant potential for advancing combustion kinetics studies.
• The technique provides crucial insights into intricate combustion environments through detailed temperature mapping.