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Laser absorption spectroscopy (LAS) technology, as a non-contact measurement method with high measurement sensitivity and fast response, combined with tomography technology, can simultaneously achieve visual measurement of flame temperature and components concentrations distribution, and further analyze combustion reaction rules. In this paper, we developed a compact LAS tomography system for the distribution images of temperature and species concentrations. The system mainly consists of two parts, a 32-path sensor and a self-made compact case. In the sensor, 32 pair of collimators with optical fibers are used. The collimator-to- collimator design can help reduce background interference from infrared radiation due to fuel combustion. In the compact case, two distributed feedback lasers, two laser controller units, a 2/1 fiber combiner, a 1/32 fiber splitter and a 32-channels data acquisition unit are integrated. The output lights of lasers are divided into 32 beams by the splitter. The sampling rate of each channel of data acquisition unit can reach up to 1MHz. The measured data is transmitted to the computer for processing and can realize uninterrupted long-term monitoring. In the experiment, a flat flame burner is chosen as the target and the wavenumbers of lasers are scanning around 7185.6cm-1 and 7444.3cm-1 respectively. The temperature and water vapor concentration distribution images are reconstructed by the system. The reconstructed image trends of symmetrically distributed. Compared with the temperature testing result of thermocouple thermometer, the temperature distribution trends of the two methods are consistent.
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