Marine Engine/ Ship Propulsion

System Simulation

Gerasimos Theotokatos

Department of Naval Architecture, Ocean & Marine Engineering

University of Strathclyde

November 2015

SIMULATION OF MARINE DIESEL ENGINE

Understanding of the physical processes

Investigating the interaction between the subsystems

Initial testing of alternative design options

Examining circumstances with high risk in installation

integrity

SIMULATION TOOLS

Transfer function models

development of control schemes

Mean value models

fast transient response estimation

engine control system design process

Zero or One-Dimensional Models

more detailed modelling of engine components

performance prediction, transient response studies

3-D models (FEM, CFD)

investigation, optimization of components design

Recommended reading

1. Internal Combustion Engine Fundamentals, John B Heywood.

2. G.P. Merker, Ch. Schwarz, G. Stiesch, F. Otto, Simulating Combustion -

Simulation of combustion and pollutant formation for engine-development,

2006

3. Theotokatos G., (2010), On the Cycle Mean Value Modelling of Large Two-

Stroke Marine Diesel Engine, Proceedings of the Institution of Mechanical

Engineers, Part M, Journal of Engineering for the Maritime Environment, Vol.

224, No M3, pp. 193-205.

4. Theotokatos G., Tzelepis V. A computational study on the performance and

emission parameters mapping of a ship propulsion system, Proceedings of

the Institution of Mechanical Engineers, Part M: Journal of Engineering for

the Maritime Environment, (2013).

MEAN VALUE MODELS

Advantages:

Engine modelling with acceptable accuracy

Limited amount of input data

Reasonable time of execution

Drawbacks:

Require data (experimental/simulation) for calibration

Categories:

Quasi-steady models (no mass accumulation is considered

between the engine components)

Modelling of engine receivers as open thermodynamic

systems

MEAN VALUE ENGINE MODELLING (MVEM)

engine ambient

compressor

air cooler

exhaust

receiver

NE

NTC

engine

cylinders

to ambient via engine

exhaust piping system

engine

crankshaft

turbine

scavenging

receiver

engine ambient

compressor

air cooler

exhaust

receiver

NE

NTC

engine

cylinders

to ambient via engine

exhaust piping system

engine

crankshaft

turbine

scavenging

receiver

Modelled engine components

MVEM APROACH

/ in outdm dt m m

/ / /ht in in out out vdT dt Q m h m h udm dt mc

/p mRT V

Engine scavenging and exhaust receivers are modelled as

open thermodynamic systems

30( )

( )

sh E PE

E sh P

Q QdN

dt I I I

30( )TC T C

TC

dN Q Q

dt I

6 non-linear first order differential equations

Angular momentum conservation

MVEM IMPLEMENTED in MATLAB/SIMULINK

INP

_u Ntc

INP

_d

OU

T_u

Qtu

rb

OU

T_d

turbine

time

Nen

gO

UT

propeller

OU

T_F

F fixed

fluid

exhaust

ambientOU

T_F

F

fixed

flluid

ambient

INP

_u FR

Nen

g

INP

_d

OU

T_u

OU

T_s

haft

OU

T_d

engine

cylinders

engpar

To Workspace

T2T1

Q_c

omp

Q_t

urb

N_t

c

T/C

shaft

Nord

Neng

pscav

FR

PID governor

Sum

_in

Sum

_out

OU

T_u

OU

T_d Open

Thermo-

dynamic

System-

exhaust

receiver

Sum

_in

Sum

_out

OU

T

Open

Thermo-

dynamic

System-

scavenging

receiver

Nord

schedule

INP

_eng

INP

_loa

dNen

g

Engine

crankshaft

INP

_u Ntc

INP

_d

OU

T_u

Qco

mp

OU

T_d

compressor

Modular construction using Elements

Flow controllers (compressor, turbine, engine cylinders)

Flow receivers (engine receivers)

Mechanical elements (engine crankshaft, T/C shaft)

Fixed fluid (ambient), Propeller, Engine governor, Nord schedule

Simulation examples

MVEM modelling- Validation

MAN Diesel & Turbo12K98ME-C engine

2-s marine engine slow steaming operation

Blower activation vs. T/C cut-out MAN Diesel & Turbo12K98ME-C engine

SIMULATION RESULTS

0 10 20 30 40 50 60 70 80 90 1000.4

0.6

0.8

1

1.2

time (s)

rack

pos

ition

(-) reference

model 1

model 2

0 10 20 30 40 50 60 70 80 90 10060

70

80

90

100

time (s)

engi

ne s

peed

(rp

m) reference

model 1

model 2

0 10 20 30 40 50 60 70 80 90 1002000

3000

4000

5000

time (s)

engi

ne to

rque

(kN

m) reference

model 1

model 2

0 10 20 30 40 50 60 70 80 90 1006000

8000

10000

12000

time (s)T

/C s

peed

(rp

m)

reference

model 1

model 2

0 10 20 30 40 50 60 70 80 90 1001

2

3

4

time (s)

scav

. rec

eive

r pr

essu

re (

bar)

reference

model 1

model 2

0 10 20 30 40 50 60 70 80 90 100400

600

800

1000

time (s)exh.

rec

eive

r te

mpe

ratu

re (

K)

reference

model 1

model 2

Comparison of the two modelling approaches results for a fast

engine transient run of 100 s

- ordered speed changes 94 rpm 69 rpm 94 rpm

MAN Diesel & Turbo 9K90MC engine

SIMULATION RESULTS

0 50 100 150 200 250 300 350 400 450 50070

75

80

85

90

95

100

time (s)

engi

ne s

peed

(rp

m)

model 1

model 2

0 50 100 150 200 250 300 350 400 450 5008000

8500

9000

9500

10000

10500

11000

11500

time (s)

T/C

spe

ed (

rpm

)

model 1

model 2

0 50 100 150 200 250 300 350 400 450 5001.5

2

2.5

3

3.5

4

time (s)

scav

. rec

eive

r pr

essu

re (

bar)

model 1

model 2

0 50 100 150 200 250 300 350 400 450 500500

550

600

650

700

750

800

time (s)

exh.

rec

eive

r te

mpe

ratu

re (

K)

model 1

model 2

Comparison of two modelling approaches results for a slow

engine transient of 500 s

ordered speed changes: 94 rpm 69 rpm 94 rpm

0-D ENGINE SIMULATION

• Thermodynamic / Control Volume Type

• Basic Engineering Elements

– Flow Receivers ( cylinders, plenums )

– Flow Controllers (valves, heat exchangers, compressors,

turbines )

– Mechanical Elements (crankshaft, shafts, loads)

Heat Transfer

Turbocharger

Intercooler

GovernorElectronic PID

Gas Exchange

Fuel Injection

Combustion

FrictionEngine/propeller Dynamics

Propeller TorqueDemand

Scavenging

Heat Transfer

Turbocharger

Intercooler

GovernorElectronic PID

Gas Exchange

Fuel Injection

Combustion

FrictionEngine/propeller Dynamics

Propeller TorqueDemand

Scavenging

0-D ENGINE SIMULATION in MATLAB/Simulink

Engine Parameters

0-D SIMULATION OF A LARGE TWO-

STROKE DIESEL ENGINE

Bore 900 mm

Stroke 2550 mm

Number of cylinders 9

Brake Power (MCR) 41130 kW

Engine speed (MCR) 94 rpm

bmep (MCR) 18 bar

bsfc (L1) 173 g/kWh

Turbocharger units 3 ABB 714

MAN B&W 9K90MC ENGINE SIMULATION

TURB. 3

COMP. 3

CYLINDERS

INLET

PORTS

EXHAUST

VALVES

EX.GAS

91 2 3 4 5

SCAVENGING RECEIVER

EXHAUST RECEIVER

1 32 4 5

54321

6

6

6

7

7

7

8

8

8

9

9

AIR

TU

RB

OS

HA

FT

1

TU

RB

OS

HA

FT

2

TU

RB

OS

HA

FT

3

TURB. 2TURB. 1

COMP. 2COMP. 1

AIRAIR

EX.GASEX.GAS

AIR

COOLER 3

AIR

COOLER 2

AIR

COOLER 1

Cylinders No. : 9

Bore : 900 mm

Stroke : 2550 mm

Compr. Ratio : 16.8

Turbochargers : 3 ABB VTR-714

Speed @ MCR : 94 rpm

Brake Power @ MCR : 41200 kW

(56000 BHP)

BMEP @ MCR : 18 bar

Boost pressure @ MCR : 3.6 bar

SIMULATION RESULTS vs. MEASURED DATA

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Time (sec)

93.594.094.595.095.596.096.5

Eng. S

peed (

rpm

)

3100

3200

3300

3400

3500

Shaft T

orq

ue (

kN

m)

2.90

2.95

3.00

3.05

3.10

3.15

Bo

ost

Pre

s. (b

ar)

80

82

84

86

88

90

Rack P

ositio

n (

%)

Measured

Predicted

Engine: MAN B&W 9K90MC

Ship: Containership / Length 280 m / 4600 TEU

Operation: at MCR speed

0-D ENGINE SIMULATION - Results

MAN Diesel & Turbo7K98MC engine

0-D ENGINE SIMULATION - Results

7K98MC engine

CFD models – Design studies

• Geometry assembly

• Mesh generation

• Analysis

– Post-processing

– Results analysis and engineering review is always critical

Diesel CFD Combustion

Simulation

Diesel CFD Combustion

Simulation

Measured vs Predicted NOx

0

500

1000

1500

2000

2500

3000

-18 -16 -14 -12 -10 -8 -6 -4 -2

Start of Injection [CAdeg]

NO

x [

pp

m]

Measured

Vectis

• Zero SOx emissions

• 85% reduced NOx emissions

• 25-30% reduced CO2 emissions

• Particulate matter emissions eliminated

LNG fuel

• Diesel mode

• Dual fuel mode with pilot fuel

Dual Fuel marine engines

MCR 8775 kW @ 514 rpm

BMEP 20 bar

Gas mode Diesel mode

BSEC 7258 kJ/kWh

BSFC Pilot fuel 1.0 g/kWh 190 g/kWh

Number of valves 2 inlet and 2 exhaust valves per cyl.

Cylinder configuration 9 in-line

Turbocharger 1 unit

Engine characteristics

Results for diesel mode and dual

fuel mode operation

Results for diesel mode and dual

fuel mode operation

Questions?