Science Island Team Makes New Progress in High-pressure Combustion Pressure Measurement Using TDLAS Technology

Recently, the team of researcher Gao Xiaoming and Liu Kun from Ankuang Institute of Hefei Institute of Materials Science, Chinese Academy of Sciences, has made new progress in high temperature environment pressure measurement by Tunable Laser Absorption Spectroscopy (TDLAS) technology, and the related research was published in the internationally renowned journal Optics Letters under the title of Dual-Color Laser Absorption Spectroscopy for Combustion Diagnostics, with the corresponding author being Associate Researcher Wang Guishi.
High-pressure combustion is an important parameter to enhance combustion efficiency and power, for the current contact pressure sensors as the main means of pressure measurement, facing low temperature resistance, high temperature sensitivity drift, interference with the combustion flow field and other issues, to carry out the high temperature combustion environment of the pressure measurement technology on the aero-engine research and development and other aspects of the important application of the value of the TDLAS due to the multi-parameter (temperature, pressure, concentration, etc.) simultaneous measurement, TDLAS has attracted much attention because of its fast speed, high sensitivity and strong anti-interference ability, and it shows great development prospects in combustion diagnosis. However, the traditional TDLAS pressure measurement is affected by the change of molecular concentration, which limits the measurement accuracy and application.
To address the problem of interference influence of molecular concentration on pressure measurement, the team, including researcher Kun Liu, associate researcher Guishi Wang, and postdoctoral fellow Ruifeng Wang, proposed a new method of pressure sensing by two-color laser absorption spectroscopy to solve the problem of molecular concentration influence. The method uses two absorption lines near the 1343 nm and 1392 nm bands of H 2O molecules, and inverts the pressure using a linear combination of the Lorentz line widths of the two absorption lines to realize molecular concentration-immunized pressure measurements. The combination coefficients are accurately calibrated in the temperature range of 473-1273 K (Kelvin, 0K = -273.15 °C) through experiments, realizing non-contact, high-precision, high-speed measurement of pressure in high-temperature environments, with a measurement accuracy of 3% and a measurement speed of 20 kHz (kilohertz). This technological breakthrough is expected to expand the TDLAS combustion diagnostics from the current temperature and concentration measurements to the multi-parameter measurements of "temperature, concentration, and pressure" in three dimensions.
This research work is supported by the National Natural Science Foundation of China (NSFC) and other programs.

A new method for pressure sensing by two-color laser absorption spectroscopy.
(a) Experimental setup; (b) Spectral signal; (c) High-speed continuous pressure measurement results at 1300K, 5.04 bar at 20 kHz.