Measurement of Gas Temperature in a Large Enclosure by Tunable Diode Laser Absorption Spectroscopy

In order to study the mechanism of mixed-convection and heat transfer when injecting hot water vapor into the containment, it is necessary to measure temperature distribution inside it. To overcome the shortcomings of traditional thermocouples technique during injection experiments of water vapor, a new temperature measurement method based on tunable diode laser absorption spectroscopy (TDLAS) was proposed in this paper. The TDLAS technique is based on the detection of H₂O absorption lines with different energies of low levels, and the spectra can be recorded using a laser detector. The data of H₂O absorption lines were selected from HITRAN2004 to obtain a pair of optimal absorption lines. A preliminary design of experimental system was presented as well as parameters selection. According to the problems when applying TDLAS, the corresponding solutions were proposed.