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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?