Zoom link

https://kaust.zoom.us/j/95073286806

Abstract

Absorption spectroscopy in the long-wave infrared (LWIR) range (8–20 μm) presents valuable opportunities for selective, quantitative and non-intrusive detection of large gas-phase species in high-temperature reactors and interstellar bodies. Measurements in this spectral region at elevated temperatures, have been limited by the absence of reliable reference absorption cross-section data.

This dissertation explores two approaches to overcome the thermal limitations of optical viewports which are transmissive in the LWIR. The first approach involved the development of a three-region laminar flow windows (LFWs) optical cell. To evaluate its performance, computational fluid dynamics (CFD) simulations and experimental tests were conducted, providing valuable insights into its performance characteristics. The second approach focused on using a non-uniform temperature optical cell to enable accurate measurements of high-temperature absorption cross-sections based on a mathematical method which reconstructs isothermal cross-section data. The method was subsequently validated and demonstrated through experiments. The later technique was employed to measure absorption cross-sections of aromatics and linear olefins at up to 1000 K. To generate and deliver precisely defined mixtures of low vapor-pressure species, a thermogravimetric analyzer (TGA) was proposed and successfully implemented.

Finally, to address the need for uncertainty quantification in spectral simulations, an online tool – MCSpectra – was developed. The tool employs Monte Carlo sampling to propagate uncertainties in HITRAN line parameters into simulated absorbance and emission spectra.

Biography

Ihsan Farouki joined the Mechanical Engineering program in PSE division at KAUST as a Ph.D. student in Spring 2022. He previously earned his M.Sc. degree from KAUST working under the supervision of Prof. Aamir Farooq.  Ihsan holds a bachelor’s degree from the Jordan University of Science and Technology, obtained in 2013. During his Ph.D., his research mainly focused on high temperature infrared spectroscopy, particularly in the long-wave infrared range and for the detection of large hydrocarbon species.