LECTUREONE-1Marine engineering thermodynamicsLEARNINGOBJECTIVESTo understand reciprocating engine principles and processes aswell as marine engine terminology and geometryTo define marine engine performance indices and assess marineengine performance and efficiencyToexplain specificfueland airconsumption-To define the various methods of supercharging and explain theeffect of superchargingtomarineengineperformanceTo derive the operating envelopes of naturally aspirated andturbocharged engines and limitations thereofTo define and perform air-standard cycle analysis:To understand Diesel and Otto cycles as well as Seiliger cycle:To calculate net heat and work on the Seiliger cycle.To calculate efficiency of the Seiliger cycle21
1 LECTURE ONE – 1 Marine engineering thermodynamics 1 LEARNING OBJECTIVES • To understand reciprocating engine principles and processes as well as marine engine terminology and geometry • To define marine engine performance indices and assess marine engine performance and efficiency • To explain specific fuel and air consumption • To define the various methods of supercharging and explain the effect of supercharging to marine engine performance • To derive the operating envelopes of naturally aspirated and turbocharged engines and limitations thereof • To define and perform air-standard cycle analysis • To understand Diesel and Otto cycles as well as Seiliger cycle • To calculate net heat and work on the Seiliger cycle • To calculate efficiency of the Seiliger cycle 2
Performanceof MarineEnginesNik.XirosLargeMarineEngines-Background:Diesel,2-stroke→Highefficiency(>50%): Large-bore, Turbocharged → High power output (up to 100MW)·Slow-speed,Long-stroke, Reversible→Direct-driveSimplicity→Lowmaintenance,Robustness··ElectroniccontrolLowemissions&fuelconsumption.Consumeheavyfuelormarinedieseloil.Intermit shaft generator, exhaust gas boilerDRAWBACKS·Verylarge size&weight:Supportingauxiliarymachineryrequirements·Complicated startingprocedure2
2 Performance of Marine Engines Nik. Xiros 3 Large Marine Engines – Background • Diesel, 2-stroke High efficiency (>50%) • Large-bore, Turbocharged High power output (up to 100MW) • Slow-speed, Long-stroke, Reversible Direct-drive • Simplicity Low maintenance, Robustness • Electronic control Low emissions & fuel consumption • Consume heavy fuel or marine diesel oil • Intermit shaft generator, exhaust gas boiler DRAWBACKS • Very large size & weight • Supporting auxiliary machinery requirements • Complicated starting procedure 4
Large Marine Engines-BackgroundLarge Marine Engines-Background
3 Large Marine Engines – Background 5 Large Marine Engines – Background 6
Large Marine Engines-BackgroundMAWK98MCWorking principle of a 2-stroke dieselexhaustvale
4 Large Marine Engines – Background 7 Working principle of a 2-stroke diesel 8
2-stroke diesel scavenging conceptsIndicatordiagrams7=8VsVsVrocVTDCA)4-strokecycleB)2-strokecycle105
5 2-stroke diesel scavenging concepts 9 Indicator diagrams 10