Simultaneous 2D NH3 and temperature measurement using ct-tunable diode laser absorption spectroscopy

In this study, the theoretical and experimental research has been conducted in order to develop the noncontact and fast response 2D temperature and concentration distribution measurement method. The technique is based on a computed tomography(CT) method using absorption spectra of NH3 and H20. The CT tunable diode laser absorption spectroscopy method using 16-path laser beams was applied to measure simultaneous 2D NH3 and temperature distributions in engine exhausts. 2D NH3 and temperature distributions were successfully reconstructed using a set of 2-wavelength 16-path absorption spectra. Time resolved NH3 distributions were also measured to get the evolution of NH3 concentration. The use of spectral fitting also plays an important role to stabilize the convergence conditions. Since CT tunable diode laser absorption spectroscopy has a potential of the kHz response time, this method enables the real-time 2D temperature and species concentration measurements to be applicable in various industrial processes including engine applications.