{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/132698"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/132698","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Measurement of ignition delay time of jet fuels in shock tube for the development of the chemical kinetic mechanism","abstract":"Reliable yet tractable kinetic mechanisms for real aviation fuels are essential for predictive simulations of advanced combustors, and this thesis develops an F-24–specific HyChem mechanism by combining new experiments in a high-pressure shock tube with regularization-constrained, data-driven optimization of lumped reaction rates. GC×GC compositional analysis, together with prior work on F-24 and Jet-A, is used to justify Jet-A HyChem as the base mechanism and to highlight the distinct character of alternative fuels such as ATJ and CycloSAF. The UIUC shock tube is re-instrumented with a tailored driver and an endwall pressure transducer, enabling robust measurement of both overall and first-stage ignition delays for F-24 at 5–20 bar down to ~650–700 K and providing comparative data for a cycloalkane-rich CycloSAF. A Covariance Matrix Adaptation Evolution Strategy (CMA-ES) is then employed to optimize selected Arrhenius parameters of the 16 lumped HyChem reactions using a multi-objective function that combines ignition-delay RMSE and L1/L2-type regularization, with tight parameter bounds to preserve physical plausibility. The optimized mechanisms correct the baseline underprediction of F-24 ignition delays in the negative-temperature-coefficient and low-temperature regimes while maintaining high-temperature performance, and identify a small subset of high- and low-temperature reactions that dominate the required adjustments. First-stage ignition delays are shown to be critical for constraining low-temperature QOOH-cycle reactions, and a staged strategy that first optimizes overall ignition delays and then refines only low-temperature reactions against first-stage data is demonstrated to reproduce fully coupled multi-objective results at reduced computational cost. Validation against independent laminar flame speed measurements and shock-tube species profiles confirms that the regularized mechanisms retain balanced fidelity across ignition, flame propagation, and intermediate chemistry, while revealing specific larger unsaturated and aromatic species that require new kinetic pathways, thereby establishing a practical framework for constructing robust, fuel-specific HyChem mechanisms for current and emerging aviation fuels.","abstract_html":"Reliable yet tractable kinetic mechanisms for real aviation fuels are essential for predictive simulations of advanced combustors, and this thesis develops an F-24–specific HyChem mechanism by combining new experiments in a high-pressure shock tube with regularization-constrained, data-driven optimization of lumped reaction rates. GC×GC compositional analysis, together with prior work on F-24 and Jet-A, is used to justify Jet-A HyChem as the base mechanism and to highlight the distinct character of alternative fuels such as ATJ and CycloSAF. The UIUC shock tube is re-instrumented with a tailored driver and an endwall pressure transducer, enabling robust measurement of both overall and first-stage ignition delays for F-24 at 5–20 bar down to ~650–700 K and providing comparative data for a cycloalkane-rich CycloSAF. A Covariance Matrix Adaptation Evolution Strategy (CMA-ES) is then employed to optimize selected Arrhenius parameters of the 16 lumped HyChem reactions using a multi-objective function that combines ignition-delay RMSE and L1/L2-type regularization, with tight parameter bounds to preserve physical plausibility. The optimized mechanisms correct the baseline underprediction of F-24 ignition delays in the negative-temperature-coefficient and low-temperature regimes while maintaining high-temperature performance, and identify a small subset of high- and low-temperature reactions that dominate the required adjustments. First-stage ignition delays are shown to be critical for constraining low-temperature QOOH-cycle reactions, and a staged strategy that first optimizes overall ignition delays and then refines only low-temperature reactions against first-stage data is demonstrated to reproduce fully coupled multi-objective results at reduced computational cost. Validation against independent laminar flame speed measurements and shock-tube species profiles confirms that the regularized mechanisms retain balanced fidelity across ignition, flame propagation, and intermediate chemistry, while revealing specific larger unsaturated and aromatic species that require new kinetic pathways, thereby establishing a practical framework for constructing robust, fuel-specific HyChem mechanisms for current and emerging aviation fuels.","abstract_has_math":false,"creators":["Yoon, Sungho"],"institution":"University of Illinois Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Aerospace Engineering","degree_department":null,"school":null,"contributors":["Lee, Tonghun"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-12","date_published":"2025-12","updated_at":"2026-07-22T22:25:07Z","subjects":["Chemical Kinetics","Shock Tube","Ignition Delay","First-Stage Igntion Delay","HyChem","F-24","CMA-ES optimization","Regularization"],"languages":["en"],"rights":["Copyright 2025 Sungho Yoon, Tonghun Lee"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/132698","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Lee, Tonghun"]},{"key":"dc:creator","label":"Author","values":["Yoon, Sungho"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-12","2025-12-09"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aerospace Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemical Kinetics","Shock Tube","Ignition Delay","First-Stage Igntion Delay","HyChem","F-24","CMA-ES optimization","Regularization"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2025 Sungho Yoon, Tonghun Lee"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/132698"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Reliable yet tractable kinetic mechanisms for real aviation fuels are essential for predictive simulations of advanced combustors, and this thesis develops an F-24–specific HyChem mechanism by combining new experiments in a high-pressure shock tube with regularization-constrained, data-driven optimization of lumped reaction rates. GC×GC compositional analysis, together with prior work on F-24 and Jet-A, is used to justify Jet-A HyChem as the base mechanism and to highlight the distinct character of alternative fuels such as ATJ and CycloSAF. The UIUC shock tube is re-instrumented with a tailored driver and an endwall pressure transducer, enabling robust measurement of both overall and first-stage ignition delays for F-24 at 5–20 bar down to ~650–700 K and providing comparative data for a cycloalkane-rich CycloSAF. A Covariance Matrix Adaptation Evolution Strategy (CMA-ES) is then employed to optimize selected Arrhenius parameters of the 16 lumped HyChem reactions using a multi-objective function that combines ignition-delay RMSE and L1/L2-type regularization, with tight parameter bounds to preserve physical plausibility. The optimized mechanisms correct the baseline underprediction of F-24 ignition delays in the negative-temperature-coefficient and low-temperature regimes while maintaining high-temperature performance, and identify a small subset of high- and low-temperature reactions that dominate the required adjustments. First-stage ignition delays are shown to be critical for constraining low-temperature QOOH-cycle reactions, and a staged strategy that first optimizes overall ignition delays and then refines only low-temperature reactions against first-stage data is demonstrated to reproduce fully coupled multi-objective results at reduced computational cost. Validation against independent laminar flame speed measurements and shock-tube species profiles confirms that the regularized mechanisms retain balanced fidelity across ignition, flame propagation, and intermediate chemistry, while revealing specific larger unsaturated and aromatic species that require new kinetic pathways, thereby establishing a practical framework for constructing robust, fuel-specific HyChem mechanisms for current and emerging aviation fuels.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-12-01","The student, Sungho Yoon, accepted the attached license on 2025-12-07 at 15:08.","The student, Sungho Yoon, submitted this Thesis for approval on 2025-12-09 at 08:04.","This Thesis was approved for publication on 2025-12-09 at 08:43.","DSpace SAF Submission Ingestion Package generated from Vireo submission #23094 on 2026-02-19 at 18:46:51"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Measurement of ignition delay time of jet fuels in shock tube for the development of the chemical kinetic mechanism"]}]}],"canonical_facts":{"dc:contributor":["Lee, Tonghun"],"dc:creator":["Yoon, Sungho"],"dc:date":["2025-12","2025-12-09"],"dc:description":["Reliable yet tractable kinetic mechanisms for real aviation fuels are essential for predictive simulations of advanced combustors, and this thesis develops an F-24–specific HyChem mechanism by combining new experiments in a high-pressure shock tube with regularization-constrained, data-driven optimization of lumped reaction rates. GC×GC compositional analysis, together with prior work on F-24 and Jet-A, is used to justify Jet-A HyChem as the base mechanism and to highlight the distinct character of alternative fuels such as ATJ and CycloSAF. The UIUC shock tube is re-instrumented with a tailored driver and an endwall pressure transducer, enabling robust measurement of both overall and first-stage ignition delays for F-24 at 5–20 bar down to ~650–700 K and providing comparative data for a cycloalkane-rich CycloSAF. A Covariance Matrix Adaptation Evolution Strategy (CMA-ES) is then employed to optimize selected Arrhenius parameters of the 16 lumped HyChem reactions using a multi-objective function that combines ignition-delay RMSE and L1/L2-type regularization, with tight parameter bounds to preserve physical plausibility. The optimized mechanisms correct the baseline underprediction of F-24 ignition delays in the negative-temperature-coefficient and low-temperature regimes while maintaining high-temperature performance, and identify a small subset of high- and low-temperature reactions that dominate the required adjustments. First-stage ignition delays are shown to be critical for constraining low-temperature QOOH-cycle reactions, and a staged strategy that first optimizes overall ignition delays and then refines only low-temperature reactions against first-stage data is demonstrated to reproduce fully coupled multi-objective results at reduced computational cost. Validation against independent laminar flame speed measurements and shock-tube species profiles confirms that the regularized mechanisms retain balanced fidelity across ignition, flame propagation, and intermediate chemistry, while revealing specific larger unsaturated and aromatic species that require new kinetic pathways, thereby establishing a practical framework for constructing robust, fuel-specific HyChem mechanisms for current and emerging aviation fuels.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-12-01","The student, Sungho Yoon, accepted the attached license on 2025-12-07 at 15:08.","The student, Sungho Yoon, submitted this Thesis for approval on 2025-12-09 at 08:04.","This Thesis was approved for publication on 2025-12-09 at 08:43.","DSpace SAF Submission Ingestion Package generated from Vireo submission #23094 on 2026-02-19 at 18:46:51"],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/132698"],"dc:language":["en"],"dc:rights":["Copyright 2025 Sungho Yoon, Tonghun Lee"],"dc:subject":["Chemical Kinetics","Shock Tube","Ignition Delay","First-Stage Igntion Delay","HyChem","F-24","CMA-ES optimization","Regularization"],"dc:title":["Measurement of ignition delay time of jet fuels in shock tube for the development of the chemical kinetic mechanism"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Aerospace Engineering"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:07Z"}