Experimental investigation of pilot-fuel combustion in dual-fuel engines, Part 2: Understanding the underlying mechanisms by means of optical diagnostics
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Autor:in (Körperschaft)
Publikationsdatum
11.2019
Typ der Arbeit
Studiengang
Typ
01A - Beitrag in wissenschaftlicher Zeitschrift
Herausgeber:innen
Herausgeber:in (Körperschaft)
Betreuer:in
Übergeordnetes Werk
Fuel
Themenheft
DOI der Originalpublikation
Link
Reihe / Serie
Reihennummer
Jahrgang / Band
255
Ausgabe / Nummer
Seiten / Dauer
115766
Patentnummer
Verlag / Herausgebende Institution
Elsevier
Verlagsort / Veranstaltungsort
Auflage
Version
Programmiersprache
Abtretungsempfänger:in
Praxispartner:in/Auftraggeber:in
Zusammenfassung
The pilot-fuel auto-ignition and combustion under engine-like conditions in compressed methane/air mixtures are investigated in a RCEM using a single-hole coaxial injector. In Part 1, the phenomenology of the pilot-fuel combustion was studied based on the thermodynamic analysis. With the addition of methane, a prolonged pilot fuel combustion duration was observed, especially at increased EGR rates. The aim of Part 2 is to improve the understanding of the underlying processes governing the pilot-fuel burning and premixed flame initiation in dual-fuel engines. The thermodynamic analysis is supplemented by optical diagnostics including the high-speed CH₂O-PLIF, Schlieren and OH*, and corroborated with homogeneous reactor and laminar flame speed calculations. The investigations focus on determining the role of (a) ignition location and number of ignition kernels, (b) stratification of the autoignition time due to the methane chemistry effects, and (c) the role of flame propagation during the pilot-fuel burning. In the initial phase, combustion is found to propagate through an autoigniting front. When combustion reaches the lean zones with a high spatial stratification of the autoignition time, premixed flame propagation becomes the dominant mechanism, owing to its higher spreading rate. Both processes influence the pilot-fuel combustion duration. At higher methane concentration, the simulations predict an increasing stratification of the ignition delay in lean regions, while the laminar flame speed in the pilot-fuel lean regions moderately increases. Overall, this explains the observed trend of longer pilot-fuel combustion duration in the dual-fuel cases and indicates an increasing role of flame-propagation in the dual-fuel combustion pilot-fuel burning.
Schlagwörter
Veranstaltung
Startdatum der Ausstellung
Enddatum der Ausstellung
Startdatum der Konferenz
Enddatum der Konferenz
Datum der letzten Prüfung
ISBN
ISSN
0016-2361
1873-7153
1873-7153
Sprache
Englisch
Während FHNW Zugehörigkeit erstellt
Ja
Zukunftsfelder FHNW
Publikationsstatus
Veröffentlicht
Begutachtung
Peer-Review der ganzen Publikation
Open Access-Status
Closed
Lizenz
Zitation
Srna, A., von Rotz, B., Bolla, M., Wright, Y. M., Herrmann, K., Boulouchos, K., & Bruneaux, G. (2019). Experimental investigation of pilot-fuel combustion in dual-fuel engines, Part 2: Understanding the underlying mechanisms by means of optical diagnostics. Fuel, 255, 115766. https://doi.org/10.1016/j.fuel.2019.115766