1. Marine Engineering System - Introduction

Marine Engineering System

Introduction

Life and Measurement

Administration        

Course content Class Class notes Assessment -Homework assignments and solutions Final Exam Labs Others : Collaborative work, attitude, communication, learning through variation and creativity and new ideas.

Variation • We only learn because of variation – when something new or different challenges our pre-conceived ideas • What we learn depends on the variation we have experienced

Subject General Objective Introduction to shipping ships and general marine engineering systems Coverage:       

Common marine engineering terms Safe working practice onboard ships Type of Merchant ships Type of Naval ships Type of auxiliary crafts Shipboard systems Engine room and Machinery layout

Course Navigation -

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Marine engineering terms and system Operating principle, characteristics and classification of marine engines and supporting systems Principle of operation ships auxiliary machineries system Marine electrical power generation and distribution system Marine propulsion system

This lecture – Introduction to marine engineering and ship system At the end of the lesson student will be able 

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to : Define common terms of ship and marine engineering system Ship types Marine engineering system Propulsion layout Hull Safety consideration Design consideration

A. Marine engineering and marine engine

Evolution of marine engine 

Effort to apply mechanical power to propulsion and operation of ship since eighteen century as never been easy.

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Why?

Design requirement 

Because ship is a have never been a simple product

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It require exceptional number of specialization to plan ,design and build a ship

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This make maritime technology distinctive integrated technology in part of many engineering disciplines require for the design of system of transport, exploration, naval craft which have one thing in common. What ?

Design requirement  

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Operate on the surface of water The field of engineering under maritime technology – naval architecture and marine engineering is with at least the following: Inland waterway and ocean transportation Naval engineering Ocean engineering Contention between naval architecture and marine engineer in system design

1. Common terms

Common terms        

Ships Vessels Submarines Tugs Ferries Boats Class societies & Mardep Propulsion system

Common terms (Contd)       

Auxiliary Power system Air system SW system FW system Fuel system Hospitality systems Navigation and steering system

2. Safe working practice

Safe working practice 

Special constraints of ship operation     

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Ship is a floating and moving object Subject to flooding, rolling & Pitching Limited space for machinery Operates away from shore facilities No neutral line to earth

Carries heavy and dangerous cargo

How to enforce Safety  

Proper safety attire Regular and effective maintenance   

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Repairs / drydocking/inspection Load Testing of lifting equipment Test of Firefighting system

Periodic certification and validation of ships and its systems

3. Ship Types & Hull Forms

Types of Ships 

Merchant ships  Bulk carriers  Oil Tankers  Chemical tankers  LNG tankers  Container ships  Passenger liners

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Auxiliary Vessels Tugs Ferries Support vessels Barges

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Naval Ships  Frigates  Destroyers  Cruisers  Aircraft carriers  Patrol crafts  Survey ships  Submaries

3.1 Classification of Ship by Usage 

Merchant Ship

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Naval & Coast Guard Vessel

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Recreational Vessel

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Utility Tugs

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Research & Environmental Ship

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Ferries

3.2 Classification of Ship by Support Type • Aerostatic Support - ACV (Air Cushion Vehicles) - SES (Captured Air Bubble)

• Hydrodynamic Support - Hydrofoil - HYSWAS (HYdrodynamic Small Waterplane Area Ship) -Planning Hull

• Hydrostatic Support - Conventional Ship - Catamaran - SWATH (Small Waterplane Area Twin Hull) - Deep Displacement

• Submarine - Submarine - AUV/ROV

3.3.1 Aerostatic Support - Supported by cushion of air generated by a fan. - ACV (Air Cushion Vehicle) hull material : rubber propeller : placed on the deck amphibious operation - SES (Surface Effect Ship) side hull : rigid wall(steel or FRP) bow : skirt propulsion system : placed under the water water jet propulsion supercavitating propeller not amphibious operation

SES Ferry

NYC SES Fireboat

E

250’ SES Ferry

3.3.2 Hydrodynamic Support • Planning Hull

- supported by the hydrodynamic pressure developed under the hull at high speed - V or flat type shape - commonly used in pleasure boat, patrol boat, missile boat, racing boat Destriero

3.3.3 Hydrodynamic Support • Hydrofoil Ship

- supported by a hydrofoil, like wing on an aircraft

- fully submerged hydrofoil ship - surface piercing hydrofoil ship Hydrofoil Ferry

HYSWAS Quest

Hydroplane vessel

3.3.4 Hydrostatic Support • Displacement ship

- conventional type of ship - carries high payload - low speed • SWATH - small waterplane area twin hull (SWATH) - low wave-making resistance - excellent roll stability - large open deck - disadvantage : deep draft and cost

• Catamaran/Trimaran - twin hull - other characteristics are similar to the SWATH • Submarine

SWATH vessel

SWATH vessel Seashadow

Tri-Hull combat concept vessel

4. Shipboard systems

Shipboard systems 

Propulsion system       

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Steam Diesel Gas turbine All electric CODAD CODAG COSAG

Aux power system   

AC/DC LV HV

contd        

Sea Water system Fire fighting system Pumping and flooding system FW system Aircon and ventilation system FW system Cargo system Navigation system and steering

Fuel oil Piping System

FRESH WATER SYSTEM

Fresh Water Cooling System

EXPANSION / HEADER TANK

TURBOCHARGER

S/W OUT

TO & F ROM DIESEL GENERA TOR J ACKET WATER COOLER

J KT. WATER COOLING P /P S CYLINDER BLOCK

S/W IN

& CYLINDER HEAD DISTRIB UTION M A NIFOLD HEATER

MAIN DIESEL ENGINE

S/W OUT

P ISTONS DISTRIBUTION M ANIFOLD

P ITON WA TER P ISTON WATER COOLING P /P S

COLLEC TION M ANIFOLD

COOLER

S/W IN

F ROM P ISTON

P ISTON DRA IN TA NK

LUBRICATION OIL SYSTEM

Lubrication Oil System

CYLINDER LUBRICATING OIL SERVICE TANK

TEMPERATURE CONTROL VALVE

CYLINDER LUB RICATION BOXES

SEA WATER OUTLET

LUB

CROSSHEAD & P ISTON

OIL

DISTRIB UTION

COOLER

M A NIFOLD

MAIN DIESEL ENGINE

SEA WATER INLET

FINE FILTERS M AIN BEAR ING & CRA NKP IN DISTRIBUTION M ANIFOLD

LUB OIL PUMPS

STRAINERS

DRY SUMP TANK

STEAM

LUBRICATING OIL

HEATING

COLLECTING TANK

MAGNETIC FILTERS

LUB OIL PURIFIER HEATER

SEA WATER COOLING SYSTEM

Sea Water Cooling System TURBOCHARGER

J A CKET

FRESH WATER COOLER CHA RGE AIR C OOLER

MAIN DIESEL ENGINE

PISTON

LUB OIL

WATER

COOLER

COOLER

SEA WATER COOLING P UM P S FILTER SEA CHEST

FILTER

SEA C HEST

STARTING AIR SYSTEM

Air Starting System STARTING AIR VALVES

P ILOT VA LVE

AIR BOTTLE No 1

No 2

OR RESER VOIR

MAIN DIESEL ENGINE

AIR DISTRIBUTOR

M AIN A IR C OM P RESSORS

No 1

No 2

Main Diesel Engine Cooling System

5. Types Marine Engine

MARINE PROPULSION ENGINE

STEAM ENGINE

STEAM TURBINE ENGINE

RECIPROCATING STEAM ENGINE SPARK IGNITION

TWO STROKE

DIESEL ENGINE

GAS TURBINE ENGINE

COMPRESSION IGNITION FOUR STROKE

CATERGORIES 

Steam Turbine Engine

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Gas turbine engine

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Steam Engine

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Diesel engine

Prime movers

Gas Turbines  Gas turbine have been selected as the future prime mover primarily because of their high power to weight ratio.  4. Weight sensitive ship designs favor gas turbines and projected light weight fuel cell power plants such as PEM.  They also provide significant reduction in the amount of routine maintenance required when compared with diesel generators.  The other significant factor is the low emissions. Diesel engine  Diesel engines offer fuel costs savings of 50% if heavy fuels can be used, and if emissions can be maintained at acceptable levels.  Maintenance may include engine modifications such as dual fuel capability for in-port use, water injection, and timing retard, and exhaust treatment such as selected catalytic reduction and oxidation catalysts.  Heavy fuel use also requires careful selection of cylinder material and lube oil

Turbine 

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A gas turbine, also called a combustion turbine, is a rotary engine that extracts energy from a flow of hot gas produced by combustion of gas or fuel oil in a stream of compressed air. It has an upstream air compressor radial or axial flow mechanically coupled to a downstream turbine and a combustion chamber in between. Energy is released when compressed air is mixed with fuel and ignited in the combustor The resulting gases are directed over the turbine's blades, spinning the turbine, and, mechanically, powering the compressor. Finally, the gases are passed through a nozzle , generating additional thrust by accelerating the hot exhaust gases by expansion back to atmospheric pressure. A steam turbine is a mechanical device that extracts thermal energy from pressurized steam , and converts it into useful mechanical work.

Steam Turbine engine 

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The Steam turbine is use to obtain mechanical work from the energy stored in steam. Steam enters the turbine with high energy content and leaves after giving up most of it. The high pressure steam from the boiler is expanded in nozzles to create a high velocity jet of steam, which produces the force which causes rotation of the shaft.

Gas turbine 

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The Gas turbine is use for obtaining mechanical work from the energy stored in Gases in which combustion take place in the combustion chamber. The hot gases enters the turbine with high energy content and leaves after giving up most of it. The high pressure gases from the combustion chamber is expanded in nozzles to create a high velocity jet of gases, which produces the force which causes rotation of the shaft.

Gas Turbine

First 3 shaft concept, January 1945

Coberra 6000 Starting Sequence Typical Arrangement RB211

GG COMBUSTOR

AIR INTAKE

RT - 56 RT - 62

POWER TURBINE IP

HP

GG COMPRESSORS GG TURBINES

Roll Royce Gas Generator

Centrifugal Compressor GEAR BOX

Steam engine

COGAG 

Combined gas turbine and gas turbine (COGAG) is propulsion system for ships using two gas turbines connected to a single propeller shaft.

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A gearbox and clutches allow either of the turbines to drive the shaft or both of them combined.

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Using one or two gas turbines has the advantage of having two different power settings.

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Since the fuel efficiency of a gas turbine is best near its maximum power level, a small gas turbine running at its full speed is more efficient compared to a twice as powerful turbine running at half speed, allowing more economic transit at cruise speeds.

Diesel engine

Electric drive Electric drive transmissions have a higher specific fuel consumption, specific weight and volume than mechanical drive systems, but has advantages in arrangement which may compensate for these disadvantages.  Advanced technology motors can be located very close to and on line with the propulsors, at the extreme aft end of the ship, or in external pods.  Electrical generator sets can be optimally spaced around the ship and electrically connected. In the longer term, combined with fuel cells, SFC, specific weight and volume are comparable with gas turbine and diesel prime movers for direct drive systems. Zone Concept :  The concept of dividing future classes of ship into zones to maximize survivability also extends to the power system.  Each zone would be autonomous and include ventilation systems, cooling systems, power distribution and other services which could be affected by damage to another part of the ship.  At least two supplies would be provided for all essential loads. Current classes, using split generation and distribution, rely on the provision of normal and alternative supplies via Automatic Change-Over Switches 

Fuel cell 

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The fuel cell stack operates by utilizing electrochemical reactions between an oxidant (air) and a fuel (hydrogen), with two electrodes separated by a membrane. The voltage of the fuel cell output can be controlled by a converter and it is therefore able to connect to any point in the ship service or propulsion distribution system. The fuel cell stack is modularity give redundancy advantage. It also has the additional advantages of zero noxious emissions, and low thermal and acoustic signatures. In the short term the fuel cell system is required to use marine diesel fuel. Diesel fuel will require reforming within the fuel cell stack, or using an external process, to produce a hydrogen rich gas which the fuel cell stack is capable of processing. The reformer will clearly add both size, weight and complexity to the fuel cell system. In the longer term technologies such as the Solid Oxide Fuel Cell (SOFC) are contenders, which are more forgiving of impurities and can use a fuel available world-wide, either methanol or gasoline.

Storage option 

The technologies being assessed for energy storage include are electrochemical batteries (both conventional and advanced), regenerative fuel cells (otherwise known as redox flow cells ) Superconducting Magnetic Energy Storage (SMES) and Supercapacitors.

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Regenerative fuel cells store or release electrical energy by means of a reversible electrochemical reaction between two salt solutions (the electrolytes). The reaction occurs within an electrochemical cell.

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The cell has two compartments, one for each electrolyte, physically separated by an ion-exchange membrane.

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In contrast to most types of battery system, the electrolytes flow into and out of the cells and are transformed electrochemically inside the cells. The power is therefore determined by the size of the cell but the endurance is determined by the size of the two electrolyte tanks

Storage system

Prime movers and emission 

All prime movers are potentially compliant with emerging emission requirements, however, complexity for achieving compliance varies with prime mover and fuel type.

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Diesels require the most attention to emissions control followed at some distance by gas turbines, where ultra low emissions levels have been achieved for land-based systems.

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Fuel cells emit the lowest levels of pollutants of all the prime movers Heavier fuel cell systems and diesels represent larger machinery and structural weight.

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Fuel cells can be used as a prime mover in an Integrated Full Electric Propulsion (IFEP) system providing DC electrical power output, and are being developed as a replacement for diesel generators and gas turbine alternators.

Sail and solar power ship

Skysail

Propulsion system layout

Propulsion system Layout 

Depends on the type of ship,its size and role   

Direct coupled Geared Azipods

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Ship Drive Train and Power Ship Drive Train System EHP Engine

Reduction Gear

Bearing

Strut Screw Seals THP

BHP

SHP

DHP 98

Ship Drive Train and Power Horse Power in Drive Train Brake Horse Power (BHP) - Power output at the shaft coming out of the engine before the reduction gears Shaft Horse Power (SHP) - Power output after the reduction gears - SHP=BHP - losses in reduction gear

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Ship Drive Train and Power Delivered Horse Power (DHP) - Power delivered to the propeller - DHP=SHP – losses in shafting, shaft bearings and seals Thrust Horse Power (THP) - Power created by the screw/propeller - THP=DHP – Propeller losses E/G

BHP

R/G

SHP

Shaft Bearing

DHP

Prop.

THP

Hull

EHP

Relative Magnitudes BHP>SHP>DHP>THP>EHP

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Effective Horse Power (EHP) • EHP : The power required to move the ship hull at a given speed in the absence of propeller action (EHP is not related with Power Train System) • EHP can be determined from the towing tank experiments at the various speeds of the model ship. • EHP of the model ship is converted into EHP of the full scale ship by Froude’s Law. Towing Tank

Measured EHP V Towing carriage

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Effective Horsepower, EHP (HP)

Effective Horse Power (EHP) POWERCURVE YARDPATROL CRAFT

1000 800 600 400 200 0 0

2

4

6

8

10

12

14

16

Ship Speed, Vs (Knots)

Typical EHP Curve of YP

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Typical 30 MW Steam Propulsion

Blow down gas 1 m3 /s release 30 MW power but in port requirement is only 6 MW

Typical Diesel Propulsion

Main and aux power sources separate and independent, re-liquefaction (5 MW)

Typical Diesel Propulsion

Main and aux power sources separate and independent, re-liquefaction (5 MW)

Typical Diesel Propulsion

Main diesel engines drive aux generators

Typical Diesel Propulsion

Typical Schematic of IEPS

Layout of Typical IEPS

Medium speed 4-s diesel

Pictorial View of First IEPS

Hull

Wave-Making Resistance (cont) Bulbous Bow

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Summary    

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Development of marine engineering system Common terms of marine engineering system Overview of marine engineering system Overview of marine engines - LO, Fuel Valve cooling, Cylinder LO etc., Overview of marine propulsion layout