Propulsion System

2014-10-15

Young Ryeol JooDivision of Ocean Systems Engineering

OSE503 Intro. to NA & OE

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Book ContentsLets get under wayGeneral arrangementsWorking areas and accommodationsDesign proceduresHull formsStatics stabilityDynamic stabilityResistance and poweringPropulsion devicesChoosing propulsion machineryWind powerHull strength requirementsMaterials of constructionStructural arrangementsMiscellaneous design matters 2

Contents

PerspectiveAlternative systemsGenerating ElectricityFuels

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1. Perspective

Propulsion prime movers, propellers, transmission systems, associated auxiliary machinery, fuel

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2. Alternative systems

2.1 single versus multiple screws2.2 Prime movers2.3 Transmissions2.4 Alternative combinations2.5 Key considerations2.6 Overall considerations

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2.1 single versus multiple screws

Advantage of single screw: Simplicity, ease of engine control, better propulsive efficiency- tankers, container ships, bulk carriers, etc.Multiple screws: High-powered ship, better maneuverability (turn in confined water), Shallow draft vessel (propeller diameter), - passenger ships, naval ships, high-speed craft, etc

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2.2 Prime moversGasoline engine, diesel engine, gas turbine, steam turbineNuclear powered ship2 stroke vs. 4 stroke: 2 stroke is smaller and lighter but less fuel-efficientNo carburetor in a diesel engineGas turbine(GT): Extremely compact2 classes of GT: Aircraft, power plants

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3 categories of diesel engineSlow speed: 75-250 rpm, Direct connect propeller, 2-stroke, for most cargo ships (tanker, container ship, bulk carrier, etc.)Medium speed: 400-900 rpm, 4-stroke, for passenger ship, drill ship, FPSO, etc., High speed: 1000-2400 rpm, 4-stroke, for high speed craft (passenger, naval, etc.) and ship service generator

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Diesel engine - summary

* SFOC : specific fuel oil consumption

HFO : heavy fuel oil

MDO : marine diesel oil MGO : marine gas oil

Low speed diesel Medium speed diesel High speed diesel

Speed (rpm) 60~150 450~800 1,000~3,000Stroke 2 4 4Fuel oil HFO HFO

MDO (maneuvering)MDO/MGO

SFOC (g/kWh) 156~174 167~200 187~250Weight / HP high base LowMakers MAN, Wartsila

[HHI, Doosan, STX]

MAN. Wartsila, MAK,Caterpillar, SEMT Pielstick

MTU, Caterpillar, SEMT Pielstick

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Diesel engine

4-STROKE DIESEL ENGINE (V-type)

4-STROKE DIESEL ENGINE (L-type)2-stroke engine

(MAN)

Means of Main: For equipment related to propulsionex) main engine (M/E), M. G/E, Main boilerCf. auxiliary engine, ship service generator, aux. boiler

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Diesel engine - manufacturersWrtsil

Wrtsil RT-flex96C / RTA96C 80,080 kW, 92~102 rpm, 14 cylindersfor over 10,000TEU container ship

http://www.wartsila.com/en/engines/low-speed-engines/rt-flex96c

MAN Diesel & Turbo

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Gas turbine

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Steam turbine

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2.3 Transmissions

Propellers are efficient at low speedEngines are small at high speedElectric transmission: Less efficient (8-15 % loss) whereas mechanical transmission lose 3-5 %Advantage of electric transmission: Layout, maneuverability, no shaft tunnel, shock absorbing(icebreaker)

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2.4 Alternative combinations

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Types of Propulsion system

Diesel-mechanical propulsionDiesel-electric propulsionCOGES (Combined gas and steam turbine system)CODAG (Combined diesel and gas turbine) CODOG (Combined diesel or gas turbine)Gas fuelled propulsion

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Diesel-mechanical and Diesel-electrical Propulsion

Diesel-Mechanical Propulsion

Diesel-Electric Propulsion

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4 kinds of marine engines

2.5 Key considerations

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Machinery arrangement in an oceanographic research vessel

Diesel-electric3 diesel generators2 propulsion motorsTandem driving a single screw

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3. Generating Electricity

Ever-increasing need for electrical energyBow or stern thrusters, cargo-handling, accommodation2 independent generating units for normal useEmergency diesel generator located above the freeboard deck and outside the engine roomElectric propulsion system : Electricity for propulsion motors and ship service to be supplied by main generator engine

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4. Fuels

4.1 Alternatives4.2 Fuel categories4.3 Grades of diesel oil4.4 Operating profiles

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4.1 Alternatives

Petroleum, coal, nuclear fission, gas, wood

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4.2 Fuel categoriesGasoline engine, gas turbine, high-speed diesel, medium-speed diesel, low-speeddiesel, boilerHeating value(BTUs, KJ/kg), Ignition delay critical in high-speed diesel, density (API degree; ease of separating out any water), Fluidity(viscosity, heated before pumping), safety(ignite), cleanliness

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4.3 Grades of diesel oilASTM (American society for testing and materials)No.1-D: low-viscosity for frequent speed and load changesNo.2-D: Standard diesel fuel used in cars and trucksNo.4-D: Fuel for low- and medium-speed diesel enginesHFO(heavy fuel oil): Pure or nearly pure residual oil, roughly equivalent to No. 6 fuel oilMDO (marine diesel oil): A blend of heavy gasoilMGO (marine gas oil): roughly equivalent to No. 2 fuel oil, made from distillate only* Fuel price per ton: HFO($587), MDO ($895), MGO ($905)

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4.4 Operating profiles

How much fuel should be carried ?Segment of the voyageHours at each power levelBunkering at each end of a round-trip voyage or at only one end ?Margin for contingency

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Low speed diesel engine(Wartsila)

Engine Control Room (ECR)

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Propulsion SystemBook ContentsContents1. Perspective2. Alternative systems2.1 single versus multiple screws2.2 Prime movers3 categories of diesel engineDiesel engine - summaryDiesel engineDiesel engine - manufacturers 12 132.3 Transmissions 15Types of Propulsion systemDiesel-mechanical and Diesel-electrical Propulsion 18 193. Generating Electricity4. Fuels4.1 Alternatives4.2 Fuel categories4.3 Grades of diesel oil4.4 Operating profiles 26