ERASMUSMARINE ENGINEERING SYSTEMS(propulsion systems and engines)

Familiarization with the propulsion systems that are

mostly applied on board ships: engines, power transfer

equipment, screws etc. and with the auxiliary systems

and equipment.

Subject’s goal

2

- Main engine(s) – drive (propel) the ship

- Shaft – usual mode of power transmission

- Screw – common type of propulsion

- Auxiliary engines – ‘production’ of electric energy

- Auxiliary systems – necessary for operation of main

engine, safety, comfort, cargo etc.

Basic explanations

3

Propulsion systems

�diesel engine propulsioned

�95% of ships are propulsioned with slow speed d.e.

� steam turbine propulsioned

�gas turbine propulsioned

�electric motor propulsioned

�AC/DC

�AC/AC

� combination

�CODOG, CODAG, COGES, CODLAG...

4

Engine room cross-section

MEShaft

Screw

Thrust

bearing

Is there a gearbox?

Is there a clutch?

Typical arrangements

�one or two ME, several DG

�multi casing steam turbine

�AC/AC

�CODOG or CODAG

Propulsion power safety?

TAKE ME HOME

DEVICE

Propulsion system elements

FPP vs. CPP

How would the direction of movement be changed?

ME should

be reversed

Pitch is changed

Propulsion System Coefficient of efficiency

)(

)(

hpomp

i

ep

t

e

d

t

b

d

i

bp

P

P

P

P

P

P

P

P

P

P

ηηηηη

η

η

⋅⋅⋅=

=

⋅⋅⋅=

T=R+S

ve

vv

w

Slip

nH

vsp ⋅

−=1

� H, P [m] – pitch of the

propeller

� n [min-1] number of the

revolutions of the

propeller

� v [m/s] speed

[ ]%100

60

60 ⋅−

=Hn

vHn

sp

The ship’s speed measuring

� Pitot’s tube (Pitotlog)

� GPS

� sonar... ρρ )(2

2

2

std

dst

ppv

vp

ppp

−=⇒=

+=

Slow speed engines

Fuel characteristics

� residual fuel

�HFO, DO, BO

� viscosity (cinematic)

�density

� content of S(ulphur) or V(anadium)

� low flammability

� self combustion point

�CETANE number

Combustion

�oxygen needed

� theoretical amount of air

� there is always a surplus of air

Theoretical process

V

po

VsVo

p

D. engines – construction

� piston mechanism parts:

�main bearings

�crankshaft

�connecting rods

�crossheads

�piston rods i pistons

� combustion space

�piston

�cylinder liner

�cylinder head (exhaust, fuel, starting valves)

� camshaft mechanism

� combustion air system

�auxiliary systems (fuel, lubricating oil, compressed air, regulation system etc.)

Common rail

How is the engine started?

Turbocharging – why?

Management - regulation

MEVT

Woodward regulator

regulator

shaft drive

fuel pump

handle

In case engine’s having common rail fuel system there is a common fuel pump and the

fuel valves (injection valves) are opened electronically and there has to be an electronic

crankshaft positioning device.

Bridge control panel

PREPARATION MANAGEMENT

ALARMING PROTECTION

Reasons for starting failure?

�engine is not preheated

� fuel is not preheated

�engine is not turned slowly in order to lubricate it

� there is not enough scavenging air

� safety system activated

�not sufficient starting air pressure

�water hammer in the cylinder

Exhaust gases emission (IMO, annex VI)

UDIO

Measures to reduce the emissions

�Primary – affects the combustion process

�Secondary – affects the exhaust gases (SCR)

Main engine preparation procedure

� preheating

� lube oil pumps starting

� starting air system preparation

� turning the engine slowly (on air or by a slow turning mechanism) with the indicating cocks opened

� indicating cocks closing

� setting the auxiliary blowers on ‘auto’

� fuel oil system preparation

� cooling water system preparation

� main engine reversing

� steering gear, anchor etc.

Auxiliary

(Main)

Marine steam generators

Water to steam (vapor)

p=konst.

Q

1

Q

2

Q

3

Q

4

Q

65

Q

LiquidEvaporation process

(Vapor)

Superheated

vapor

(gaseous

phase)

T – s diagram

s[kJ/kgK]

T[K]

12

3 4

6

5

p1p2p3p4K

saturation line

Critical point

water

saturated vapor

superheated vapor

Steam process

OSNOVNA SHEMA PARNOG PROCESA T-s DIJAGRAM PARNOG PROCESA

VODA

MOKRA PARA

PREGRIJANA PARA

Sea water

� 25000 g/m3 NaCl + MgCl2, MgSO4, CaSO4...

� around 35000 g/m3

Natural (spring) water

�water dissolves CO2 and O2

�dissolves CaCO3 and other minerals

�Ca(HCO3)2 and Mg(HCO3)2 - alkaline

�CO2 - acidic

Distilled water

�produced in the ship’s fresh water generating

equipment

�generates water with 4 mg/l or less

� vacuum evap. - 2 mg/l

� if more quality water is needed (1 mg/l )- ION

EXCHANGERS are used

Cylindrical boiler

Water circulation

FOSTER WHEELER type

•D, ESD I, ESD II, ESD III,

ESD IV, ESRD

•D- 40-55 t/h, 40-70 bar,

Tpp=723-773 K

•ESD=external superheater D

Heat coefficient of efficiency

d

ulvizlp

dov

odvt

ulvizlpodv

ddov

BH

hhD

Q

Q

hhDQ

HBQ

)(

)( :Odvedena

:Dovedena

,,

,,

−=

=

−⋅=⋅=

η

η

Dangers

�pipes overheating and bursting

� too high pressures – steam drum explosion

� furnace explosion

� fire in the furnace or fire of combustible residues on the pipes in the exhaust line

� safety equipment

Safety valves

Burner management

Purging!!!The simplest way:

Through the steam pressure

Starting procedure

� combustion air ventilator starting

� fuel pump starting – fuel preparation

� furnace purging

� fuel/air mixture setting

� ignition

�working pressure

Exhaust gases boilers

PRESSURES UP TO 20 bar

FORCED WATER CIRCULATION –

SMALL DIMENSIONS

Fuel and exhaust gas boilers connection

�Cijevni snop s prisilnim strujanjem

�SEKUNDARNI BUBANJ: POSUDA ZA SEPARACIJU I IZMJENJIVAČ TOPLINE

�Zagrijač vode, pregrijač

Auxiliary

(Main)

Marine steam turbines

Propulsion turbines

�Several casings (high, medium and low

pressure)

�Several stages – Parsons type turbine, although

few stages at the entrance could be of DE Laval

type

� Curtis type for reversed drive of the ship

�Gas turbine combinations

Propulsion turbines

GEAR BOX

THRUST BEARING

De Laval type

10000-30000 min-1, ηe=0,3-0.4Small power

Pump and e. generators

De Laval – change of energy

kWP

c

u

500

)5,0(2,01

=

≅

De Laval - multistage

Parsons type

Parsons - multistage

Curtis type – 1900.

3000-10000 min-1, ηe =0,4 i više

REGULATION

�CHOKING (PRESSURE)

�VAPOR QUANTITY

�COMBINED

REGULATION

REGULATIONBut, what is the regulated parameter?

Again, like in the case of diesel engine, or

any other engine having rotating parts

(shafts), it is the number of revolutions!