2026-09-20T19:43:49Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/132549 2026-02-20 col_2142_5131 col_2142_14787 com_2142_5130 com_2142_9630 com_2142_234

application/pdf en text Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2026-02-19 without embargo terms The student, Colton Willhardt, accepted the attached license on 2025-12-01 at 08:09. The student, Colton Willhardt, submitted this Dissertation for approval on 2025-12-01 at 08:17. This Dissertation was approved for publication on 2025-12-01 at 14:21. DSpace SAF Submission Ingestion Package generated from Vireo submission #22989 on 2026-02-19 at 18:25:48 Spectroscopic measurements and modeling of carbonaceous particle combustion in a shock tube Willhardt, Colton Dean 2025-12-01 Glumac, Nick Glumac, Nick Lee, Tonghun Brewster, M Quinn Panerai, Francesco carbon soot diamond spectroscopy laser absorption spectroscopy emission spectroscopy pyrometry sublimation oxidation shock tube high temperature high pressure multiphase eng Carbonaceous nanoparticle (CNP) combustion shapes optical signatures and heat release in detonation-relevant multiphase flows, yet quantitative constraints on particle temperature, sublimation rates, reaction kinetics, and wavelength-dependent optical properties remain limited under short-duration, high-temperature and pressure conditions. This dissertation integrates new shock-tube diagnostics with physics-based models to quantify CNP combustion across free-molecular to transitional heat-transfer regimes. These advances deliver actionable constraints for multiphase detonation models by linking measured optical signatures to underlying particle dynamics in extreme multiphase environments. Single color diffuse-backlit extinction imaging (DBI-EI) is used for inferring mass loss rates from optical signature decays. For resolving wavelength dependent optical efficiencies, DBI-EI is developed further by combining a supercontinuum source and an imaging spectrograph, extending classical back-illumination from one/two-color to dense spectral coverage while maintaining robustness to beam steering. The optical efficiencies feed into broadband emission measurements for inferring particle temperature. Complementary gas-phase absorption of diatomic carbon (2) is implemented by targeting the Swan bands with broadband direct absorption, enabling temperature and number-density retrievals during CNP sublimation. Together, these measurements yield time-resolved optical signatures for inferring CNP dynamics behind reflected shocks over a range of pressures and temperatures representative of post-detonation environments. Comparisons with physics-based models are performed by applying current laser-induced incandescence and multiphase flow models, which couple particle optical signatures to energy- and mass-balance equations. Models reproduce observed trends across varying temperature and pressure conditions, although they tend to overpredict the absolute magnitude of ablation rates in all conditions. The model-measurement comparisons provide insight and anchors for improving current multiphase combustion modeling in the dilute limit. 2025-12 Thesis https://hdl.handle.net/2142/132549 Copyright 2025 Colton Willhardt Mechanical Sci & Engineering Mechanical Engineering University of Illinois Urbana-Champaign Ph.D. Dissertation