Επίδραση μεταβλητότητας των λειτουργικών χαρακτηριστικών 2-Χ  ναυτικού κινητήρα κατά την μετάβαση μέσω απαγορευμένης περιοχής στροφών (BSR)

Κουζούπης, Αντώνιος; Kouzoupis, Antonios

dc.contributor.author	Κουζούπης, Αντώνιος	el
dc.contributor.author	Kouzoupis, Antonios	en
dc.date.accessioned	2019-07-01T10:19:27Z
dc.date.available	2019-07-01T10:19:27Z
dc.date.issued	2019-07-01
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/48947
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.16496
dc.rights	Default License
dc.subject	Δίχρονος ναυτικός κινητήρας	el
dc.subject	Στρεπτικές ταλαντώσεις	el
dc.subject	Ναυτική μηχανολογία	el
dc.subject	Two stroke marine engine	en
dc.subject	EEDI	en
dc.subject	BSR	en
dc.subject	Barred speed range	en
dc.subject	Torsional vibrations	en
dc.subject	DLF	en
dc.subject	Dynamic limiter function	en
dc.subject	Diesel	en
dc.subject	Περιοχή απαγορευμένων στροφών	el
dc.subject	Derated	en
dc.subject	Ντίζελ	el
dc.subject	2-Χ	el
dc.subject	2-X	en
dc.title	Επίδραση μεταβλητότητας των λειτουργικών χαρακτηριστικών 2-Χ ναυτικού κινητήρα κατά την μετάβαση μέσω απαγορευμένης περιοχής στροφών (BSR)	el
dc.title	Effect of varying the operational characteristics of a 2-stroke marine diesel engine during its passage of the barred speed range	en
heal.type	bachelorThesis
heal.classification	Ναυτική μηχανολογία	el
heal.classification	Marine engineering	el
heal.classificationURI	http://data.seab.gr/concepts/3d257f31491bff09371cddeac5c6626dc154db39
heal.classificationURI	http://data.seab.gr/concepts/3d257f31491bff09371cddeac5c6626dc154db39
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2019-03-07
heal.abstract	This thesis investigates methods for faster acceleration of a large marine two-stroke diesel engine through the Barred Speed Range (BSR). The Barred Speed Range (BSR) is a speed range of engine operation set by classification societies where due to resonance, torsional vibrations in the shaftline are excessively high. Prolonged operation inside the BSR may have a detrimental effect on the fatigue lifetime of the shaftline and even lead to a breakdown. Before the Energy Efficiency Design Index (EEDI) was introduced, propulsion engines had generally adequate torque margins and the passage through BSR was usually rather swift, and thus there was little issue with torsional fatigue cycle buildup. The introduction of EEDI resulted, in part, to the so called Eco-efficient ships with engines being derated and having reduced power margins. However, this in turn led to potential problems such as a reduced ship acceleration capability, loitering within BSR and possibly also reduced maneuverability under certain conditions, particularly in bad weather conditions. The use of electronic engines, that permits some variability within limits of their operational characteristics, has provided some flexibility to address this problem. In this thesis, the acceleration capabilities of a marine two-stroke diesel engine were studied under transient loading conditions. A Ship-Hull model and a Four Quadrant Wageningen B Series Screw Propeller model were developed in order to simulate the coupled hull-engine-propeller system. Simulations using the engine process simulation code MOTHER were performed. Variability in Fuel Injection Timing, Valve Timing and Compression Ratio was examined by using VIT (Variable Injection Timing), VVT (Variable Valve Timing) and VCR (Variable Compression Ratio) systems. Furthermore, the above methods combined with increased fuel injected or increased air mass flow were also investigated. In particular, the increase in the air mass flow was achieved by intervening in the operation of the Turbocharger. The effect of these parameters during the acceleration of the two stroke diesel engine through its BSR was examined. In conclusion, earlier injection timing showed a significant increase in the in-cylinder pressures accompanied by significant losses, leading to a small acceleration and power improvement. Increased compression ratio produced slightly increased work with slightly reduced losses, marginally increasing the engine’s acceleration and power. Variability in the exhaust valve timing resulted in negligible effects since the little extra or less work produced was balanced by slightly higher or lower losses respectively. Lastly, increased fuel and air mass flow led to a significant improvement of the engine’s acceleration and produced increased work with more power directed towards acceleration. The combined cases did not show significant differences in their acceleration and power output compared to simply injecting more fuel or inserting more air. Conclusively, the most effective method of improving the engine’s acceleration and aiding in a quicker passage through the BSR resulted to be increasing the fuel injected or the air mass flow in the cylinders.	en
heal.abstract	Σύγχρονοι κανονισμοί με στόχο την προστασία του περιβάλλοντος και την βελτίωση της απόδοσης των μηχανών, όπως το EEDI, έχουν επιβραδύνει την μετάβαση των ναυτικών κινητήρων εντός του Barred Speed Range (BSR). Πρόκειται για μια περιοχή στροφών στην οποία, λόγω συντονισμού από τις στρεπτικές ταλαντώσεις, εμφανίζονται επικίνδυνες τάσεις στον άξονα της μηχανής. Στόχος της διπλωματικής αυτής ήταν η μελέτη της ικανότητας επιτάχυνσης ενός δίχρονου ναυτικού κινητήρα Diesel καθώς αυτός επιτάχυνε εντός του BSR του. Συγκεκριμένα, ερευνήθηκε η θερμοδυναμική επίδραση μεταβλητότητας στον χρονισμό έγχυσης καύσιμου (Variable Injection Timing – VIT), στον χρονισμό των βαλβίδων εξαγωγής (Variable Valve Timing – VVT) και στον λόγο συμπίεσης του κινητήρα (Variable Compression Ratio – VCR). Επίσης, μελετήθηκε η επίδραση έγχυσης περισσότερου καύσιμου και εισαγωγής επιπλέον αέρα. Παράλληλα, αναπτύχθηκε ένα μοντέλο προπέλας και ένα μοντέλο γάστρας πλοίου με σκοπό να αναπαρασταθεί ρεαλιστικά το πρόβλημα του μεταβατικού φορτίου ενός κινητήρα κατά την επιτάχυνση.	el
heal.advisorName	Κυρτάτος, Νικόλαος	el
heal.committeeMemberName	Παπαλάμπρου, Γεώργιος	el
heal.committeeMemberName	Πολίτης, Γεράσιμος	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ναυπηγών Μηχανολόγων Μηχανικών. Τομέας Ναυτικής Μηχανολογίας. Εργαστήριο Ναυτικής Μηχανολογίας	el
heal.academicPublisherID	ntua
heal.numberOfPages	93 σ.	el
heal.fullTextAvailability	true