Validation of the real-time 2D temperature measurement method using the CT tunable diode laser absorption spectroscopy

The two-dimensional (2D) temperature and concentration distribution plays an important role for the combustion structure and combustor efficiency in engines, burners, gas turbines, and so on. Recently, as a multispecies measurement technique with high sensitivity and high response, the tunable diode laser spectroscopy (TDLAS) has been developed and applied to actual engine combustions. With these engineering developments, transient phenomena such as start-ups and load changes in engines have been gradually elucidated in various conditions. In this study, a theoretical and experimental research has been conducted in order to develop the noncontact and fast response 2D temperature and concentration distribution measurement method. The method is based on the computed tomography (CT) using the absorption spectra of water vapor at 1388 nm. The computed tomography tunable diode laser spectroscopy (CT-TDLAS) method was employed in engine exhausts to measure 2D temperature distribution. The measured 2D temperature shows good agreement with the temperature measured by a thermocouple. The temporal and spatial resolutions of this method have also been discussed to demonstrate its applicability to various types of combustor.