Toward Customized Spatial Resolution in TDLAS Tomography

Tunable diode laser absorption spectroscopy (TDLAS) tomography has been widely employed to spatially and temporally resolve gas parameters in combustion processes. The requirements placed on the spatial resolution of a tomographic image vary in industrial applications, depending on the size of the target field and the necessity to detect small features. Based on an optimized beam arrangement, this paper proposes a scheme to customize the spatial resolution in the design of TDLAS tomography systems. To the best of our knowledge, the proposed scheme, for the first time, quantifies the impact on the spatial resolution of varying the number of samples of the imaging space, in both angular and linear dimensions. More importantly, the proposed scheme can be used to determine the most effective optical layout that would achieve a desired spatial resolution. The reduction in the system complexity will enable the sensor to be installed in practical combustors while maintaining reliability. Finally, we apply the proposed scheme in a case study based on experimental data previously acquired from an automotive engine.