!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 TOOLSTransfer 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

MEAN VALUE MODELSAdvantages:!

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

enginecylinders

to ambient via engine exhaust piping system

enginecrankshaft

turbine

scavengingreceiver

engine ambient

compressor

air cooler

exhaust receiver

NE

NTC

enginecylinders

to ambient via engine exhaust piping system

enginecrankshaft

turbine

scavengingreceiver

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

sh E PE

E sh P

Q QdNdt I I I

η −=

+ +TC T C

TC

dN Q Qdt 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_FF fixed

fluidexhaustambientO

UT_

FFfixedflluid

ambient

INP_

u

FR

Nen

g

INP_

d

OU

T_u

OU

T_sh

aft

OU

T_d

enginecylinders

engparTo Workspace

T2T1

Q_c

omp

Q_t

urb

N_t

c

T/Cshaft

NordNeng

pscavFR

PID governor

Sum

_in

Sum

_out

OU

T_u

OU

T_d

Open Thermo-dynamicSystem- exhaust receiver

Sum

_in

Sum

_out

OU

T

Open Thermo-dynamicSystem-scavengingreceiver

Nordschedule

INP_

eng

INP_

loadN

eng

Enginecrankshaft

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

MVEM modelling

12K98ME-­‐C  engine  

2-s marine engine slow steaming operation

Blower  activation  vs.  T/C  cut-­‐out

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

(-) referencemodel 1model 2

0 10 20 30 40 50 60 70 80 90 10060

70

80

90

100

time (s)

engi

ne s

peed

(rpm

)

referencemodel 1model 2

0 10 20 30 40 50 60 70 80 90 1002000

3000

4000

5000

time (s)

engi

ne to

rque

(kN

m)

referencemodel 1model 2

0 10 20 30 40 50 60 70 80 90 1006000

8000

10000

12000

time (s)T/

C s

peed

(rpm

) referencemodel 1model 2

0 10 20 30 40 50 60 70 80 90 1001

2

3

4

time (s)scav

. rec

eive

r pre

ssur

e (b

ar)

referencemodel 1model 2

0 10 20 30 40 50 60 70 80 90 100400

600

800

1000

time (s)exh.

rece

iver

tem

pera

ture

(K)

referencemodel 1model 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

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

(rpm

)

model 1model 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 (r

pm)

model 1model 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 pre

ssur

e (b

ar) model 1

model 2

0 50 100 150 200 250 300 350 400 450 500500

550

600

650

700

750

800

time (s)

exh.

rece

iver

tem

pera

ture

(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

TurbochargerIntercooler

GovernorElectronic PIDGas Exchange

Fuel Injection

Combustion

Friction Engine/propeller Dynamics

Propeller TorqueDemand

Scavenging

Heat Transfer

TurbochargerIntercooler

GovernorElectronic PIDGas Exchange

Fuel Injection

Combustion

Friction Engine/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 mmStroke 2550 mmNumber of cylinders 9Brake Power (MCR) 41130 kWEngine speed (MCR) 94 rpmbmep (MCR) 18 barbsfc (L1) 173 g/kWhTurbocharger units 3 ABB 714

MAN B&W 9K90MC ENGINE SIMULATION

TURB. 3

COMP. 3

CYLINDERS

INLETPORTS

EXHAUSTVALVES

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

TURBOSHAFT 1

TURBOSHAFT 2

TURBOSHAFT 3

TURB. 2TURB. 1

COMP. 2COMP. 1

AIRAIR

EX.GASEX.GAS

AIRCOOLER 3

AIRCOOLER 2

AIRCOOLER 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 DATAEngine: MAN B&W 9K90MC Ship: Containership / Length 280 m / 4600 TEU Operation: at MCR speed

0-D ENGINE SIMULATION - Results

7K98MC  engine  

0-D ENGINE SIMULATION - Results

7K98MC  engine