Single-pulse, two-line temperature-measurement technique using KrF laser-induced O(2) fluorescence.

Area of Science:

• Physical Chemistry
• Spectroscopy
• Thermometry

Background:

• Accurate gas temperature measurement is crucial for combustion analysis and high-temperature process control.
• Existing methods may lack precision or real-time capabilities for dynamic environments.

Purpose of the Study:

• To demonstrate a new single-pulse, two-line laser-induced fluorescence (LIF) technique for gas temperature determination.
• To evaluate the accuracy and uncertainty of this novel LIF method across a specific temperature range.

Main Methods:

• Utilized a single-pulse, two-line laser excitation targeting transitions within the Schumann-Runge system of O(2).
• Employed multichannel detection to capture fluorescence spectra for temperature calculation.
• Validated measurements against thermocouple data in atmospheric air.

Main Results:

• Achieved an RMS error of 1.3% for 100-pulse averaged LIF temperature measurements compared to thermocouples.
• Demonstrated single-pulse temperature measurement uncertainties ranging from 13% at 1300 K to 7% at 1800 K.
• Identified photon shot noise as the main uncertainty source in quiescent conditions.

Conclusions:

• The demonstrated two-line LIF technique provides a viable and accurate method for high-temperature gas thermometry.
• The technique shows promise for real-time, single-pulse temperature measurements in relevant environments.
• Further research can focus on reducing uncertainties for even higher precision applications.