Tomographic absorption spectroscopy for the study of gas dynamics and reactive flows

Laser absorption spectroscopy for combustion diagnosis in reactive flows: A review

“…The physical and mathematical background of the non-linear LAS tomographic techniques has been detailed in (24,(181)(182)(183). Here, we provide a brief summary of the physics and mathematics to facilitate the discussion in the rest of the paper.…”

“…Line-of-sight LAS has been validated to quantitatively measure the path-averaged temperature, species concentrations, pressure and velocity in the combustion fields (11). Spatially resolved 1D and 2D distributions of the parameters in the reacting flows are enabled by the combination of LAS and hard-field tomography (24). When the target species is excited by a laser beam, LIF is implemented by detection of the spontaneous emission of radiation, i.e.…”

“…Line-of-sight LAS techniques, mainly classified as direct absorption spectroscopy (DAS) and wavelength modulation spectroscopy (WMS), were introduced to monitor combustion parameters that are constants or can be approximated as constants along the laser path (35,59). To fulfill the increasing demand for monitoring nonuniform flow fields, LAS was further combined with 1-and 2-dimensional tomography sensors (24,60,61). In this way, spatially-resolved distributions of the combustion parameters can be successfully retrieved from the projections obtained by discrete laser beams from different views.…”

“…For instance, an earlier review by Allan elaborated the basic theory for LAS, typical sensor configurations and their applications in measurement of reactive flows and flame (13). provided an extensive review of the mathematical foundations, experimental demonstration and practical application of tomographic absorption spectroscopy for the study of gas dynamics and reactive flows (24). In this review, we aim at charting the milestones in the evolution of LAS from the viewpoints of key principles, sensors and instrumentations developed for combustion diagnosis.…”

Optics and Spectroscopy for Fluid Characterization

“…The large number of review articles that are frequently published in these areas is evidence of this. Recent examples have focused on applications of optical diagnostics to gas phase environments [1][2][3][4][5], liquids [1,4,6,7], and multiphase systems [7][8][9][10]. A key feature of such light-based methods is that they are usually non-intrusive, and hence they do not notably affect the system under investigation.…”