| Zugriffsnummer | 55815 |
| Dokumenttyp | Zeitschriftenartikel |
| Peer Review | mit Peer Review |
| Sprache | Englisch |
| Titel | Shock tube and laminar flame studies of CH2F2, CH4, and their blends with genetic algorithm-based mechanism optimization |
| Autor(in); Institution |
Farzana, Nafi; 3.3, Physikalische Chemie, PTB-Braunschweig
Glaznev, Roman; Institute for Combustion Technology, RWTH Aachen University, Aachen, GERMANY
Wang, Guanyu; 3.3, Physikalische Chemie, PTB-Braunschweig
Beeckmann, Joachim; Institute for Combustion Technology, RWTH Aachen University, Aachen, GERMANY
|
| Quelle/Jahr | Journal of Fluorine Chemistry: 289 (2025), 1 - 15 |
| Artikelnummer | 110509 |
| ISSN | 0022-1139 (print) ; 1873-3328 (online) |
| DOI | |
| Verlag | Amsterdam: Elsevier |
| Freie Schlagworte | Shock tube ; Ignition delay time ; Speciation profile ; Flame speed ; Kinetic modeling ; Low-GWP refrigerants ; Laser absorption spectroscoy |
| Zusammenfassung | As global climate goals drive the transition away from high-GWP refrigerants, understanding the combustion behavior of low- and medium-GWP alternatives is essential for emissions control and fire safety assessment. This study presents a combined experimental and modeling investigation of difluoromethane (CH2F2, R32), methane (CH4, R50), and their blends. Shock tube experiments were performed over 1477-2236 K at 0.98-1.15 bar for φ = 0.5-2.0, with ignition delay times (IDTs) determined from time-resolved CO measurements using laser absorption spectroscopy. Complementary laminar flame speed data for CH2F2 and CH2F2/CH4 blends supported model validation. CH2F2 ignited 4-10 times faster than CH4, while blends exhibited intermediate but nonlinear IDTs due to radical cross-interactions. Time-resolved CO profiles showed broad peaks for CH2F2-containing mixtures, unlike the sharp CO peaks of CH4, indicating prolonged intermediate chemistry involving CHF, CHF2, CHFO, CF2O, and HF. Laminar flame speeds confirmed slower propagation for CH2F2 compared to CH4, while CH4 addition increased sensitivity to oxidizer composition. Kinetic analysis revealed that CH2F2 ignition is dominated by fluorine-centered pathways involving unimolecular decomposition and H-abstraction forming CHF/CHF2 radicals, with CF2O and HF as major termination products, whereas CH4 follows conventional H/O chain branching. Genetic algorithm optimization of 18 sensitive reactions within uncertainty bounds reduced IDT prediction errors by 71 % for CH2F2 and 63 % for CH2F2/CH4 blends. The optimized mechanism improved CO and flame speed predictions, achieving good agreement with experimental data within reported uncertainties. This integrated framework refines the high-temperature oxidation chemistry of fluorinated refrigerants and provides a validated mechanism for reliable fire safety evaluation. |
| Kostenfreier Zugang | Freier Zugang |
| Themenbereich der Metrologie | Physikalische Sicherheitstechnik, Explosionsschutz |
| Förderinformationen (1) |
Förderername: Deutsche Forschungsgemeinschaft (DFG)
Förderer ID: 0000 0001 2096 9829 Förderer ID Typ: ISNI Förderungsnummer: FOR5507 |
Zitierung
Farzana, N., Glaznev, R., Wang, G., Agarwal, S., Fernandes, R., Beeckmann, J., & Shu, B. (2025). Shock tube and laminar flame studies of CH₂F₂, CH₄, and their blends with genetic algorithm-based mechanism optimization. Journal of Fluorine Chemistry, 289, 1–15. https://doi.org/10.1016/j.jfluchem.2025.110509