Two dimensional temperature measurement characteristics in pulverized coal combustion field by computed tomography-tunable diode laser absorption spectroscopy

Two dimensional temperature and concentration distributions are important parameters for pulverized coal combustion used for power plant to understand the combustion field and develop the high efficient combustion technologies. However, it is difficult to measure two dimensional temperature and concentration in pulverized coal combustion field using conventional measurement technologies because pulverized coal combustion produces lots of dust and strong emission from its frame. This paper focused on the application of two dimensional temperature distribution measurement method based on the combination of computed tomography and tunable diode laser absorption spectroscopy using absorption spectra of water vapor at 1388nm and 1343nm, which show the better characteristics of spatial-temporal resolution, fast response, high sensitivity, self-calibration and optical accessibility compared with thermocouples and other laser diagnostics. Accuracy of temperature measurement using tunable diode laser absorption spectroscopy was improved by applying the corrected spectroscopic database. Computed tomography reconstruction accuracy of 16 laser-paths configuration was evaluated, which presented the consistent temperature between assumed and reconstructed distributions. This computed tomography-tunable diode laser absorption spectroscopy was successfully applied to pulverized coal flame for two dimensional temperature measurement with 1 ms temporal resolution for time-series two dimensional temperature measurement. The pulverized coal flame temperature distribution was compared to Methane-Air flame to demonstrate its feasibility and rationality due to the main heat release produced by methane fuel. It is verified the applicability to various types of combustor, especially the pulverized coal combustion field. It will be benefit for optimal operation control and combustion efficiency improvement by combustion organization or new design of combustion system.

© 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/