Volumetric laser absorption imaging of temperature, CO and CO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math> in laminar flames using 3D masked Tikhonov regularization

Mid-infrared laser absorption imaging of flame temperature and species concentration is expanded to three dimensions with linear tomographic methods using Tikhonov regularization. A spatial convolution two small-scale (< cm) laminar Bunsen-style flames, fueled by either ethylene or ethane, comprised the target flowfields. The doublets were alternately backlit tunable radiation from a quantum cascade near 4.85 ?m an interband 4.19 resolve rovibrational transitions carbon monoxide dioxide, respectively. 2D images collected at 11 different projection angles, yielding aggregate 50,688 unique lines sight capturing scene pixel resolution approximately 70 ?m. reconstruction absorbance areas regularization was performed various numbers angles compared reference image based on Abel inversion single axisymmetric flame. Increasing number improved respect resolving voids, such as inner core flame, though still resulted in under-predicted void depths artifacts outside flowfield. 3D masked method then applied further constrain multiple mitigate artifacts. introduction mask found enhance gradients within flowfield improve overall accuracy, effectively reducing requisite angles.