prediction of fuel consumption of ships in actual · pdf fileprediction of fuel consumption of...
TRANSCRIPT
Prediction of Fuel Consumptionof Ships in Actual Seas
National Maritime Research Institute
21, Dec., 2012
Masaru Tsujimoto and Naoto Sogihara
International Research Exchange Meeting on Ship and Ocean Engineering
Contents
1. Backgrounds
2. Calculation of FOC in actual seas
Engine characteristics
3. Validation by onboard measurements
4. Conclusions
2
Backgrounds
The Marine Environment Protection Committee (MEPC) of theInternational Maritime Organization (IMO) has adopted mandatorymeasures to reduce emissions of greenhouse gases.
Reduction of Greenhouse Gas Emissionsfrom International Shipping
IMO
3
Start from 1st, Jan., 2013
Energy Efficiency Design Index (EEDI)Ship Energy Efficient Management Plan (SEEMP)
EEDI is the design index in a calm sea condition.Ship owners/operators fear of performance optimizationin a calm sea condition.They need EEDIweather with fw as complementary index.
Considering the sailing condition....
4 BackgroundsImportance of EEDIweather
fw is non-dimensional coefficientfor decrease of ship speed inrepresentative sea conditions;BF6 of head winds/waves.
fw =Vw / Vref
0 1 2 3 49
10
11
12
13
14
15
16
significant wave height [m]
V [knot] BF3 BF4 BF5 BF6 BF7
fw =0.86
Vw
Vref
At present, methods combined with tank tests are necessary for the accurate evaluation of energy saving technology above water
Evaluation for the technology
to reduce added resistance in waves
Special bow shape
5 Backgrounds
Energy saving device
How to reduce fuel consumption by the operation?
PLAN
Self-evaluation and improvement
ACTION
DO
CHECK
Monitoring
ImplementationPlanning
ship management office
SEEMP is PDCA cycle
Prediction of ship speed/fuel consumption in actualoperational conditions is expected for SEEMP cycle.
weather routeing, optimum trim etc.
6 Backgrounds
Operating Point of M/E(A) No winds and no waves(calm sea)
torque limit
NE
BHP
NE
OLP limit
Another operation limits, Fuel Index limit, is used for fuel saving.
A
winds and waves become more larger
V
BHP
V
winds and waves become larger
in winds and waves
A(D) M/E rev. is decrease due to OLP limit
D
D
(C) M/E rev. is decrease due to torque limit
C
C
(B) M/E power is increased at the same rev. due to governor (FOC increase)
B
B
large V
Calculation of FOC in actual seas7
Calculation of FOC in actual seas
Fuel Index is non-dimensional value of fuel injection
FI : Fuel Index expressed as 100% at MCR
(%)100E
EMCR
MCR NN
MCRBHPFI
: SFCBHP: brake powerNE: M/E revolution
8
Calculation of FOC in actual seas
VcVw10
V [knot]
P [kW]
in a calm sea
in actual seas
Vw2
Different engine characteristics cause different shipspeed/fuel consumption, governor control as well.
P1
P2
9
Constant NE mode
Constant P mode
100110120130140150160170180190200
0 20,000 40,000 60,000 80,000
BHP (kW)
SFC (g/(kWh))
SFC
Container ship of 300m length
Calculation-FOC and ship speed-
Calculation of FOC in actual seas10
0
20
40
60
80
100
120
0 20 40 60 80 100 120NE (rpm)
Fuel Index (%) Fuel Index
(1) constant M/E rev. mode
power curves in actual seas
11 Calculation of FOC in actual seas
different operating points
(2) constant M/E rev. mode with limit of Fuel Index(3)constant M/E power mode
Working Limit of FI
12 Calculation of FOC in actual seas
decrease of ship speed FOC per day
Limit of Fuel Index causes decrease of M/E rev.
90W 120W 150W 180 150E 120E 90E
15N
0
30N
45N
60N
75N
90N
Container ship of length 300m
Route; Oakland (U.S.A.) to Tokyo (Japan)
Embarkation; March, 2012
13 Validation by onboard measurements
Waves
significant wave height (m)
primary wave direction (deg.)
mean wave period (s)
1 2 3 4 5 6 7 8 9
Day
1 2 3 4 5 6 7 8 9
Day
1 2 3 4 5 6 7 8 9
Day
forecast (JMA)
forecast (JMA)
forecast (JMA)
0 means head waves
14 Validation by onboard measurements
Bering sea
true wind direction (deg.)
true wind speed (m/s)
Winds
1 2 3 4 5 6 7 8 9
Day
1 2 3 4 5 6 7 8 9
Day
forecast (JMA)
forecast (JMA)
0 means head winds
15 Validation by onboard measurements
Bering Sea (H=5.0m Uwind=25m/s)
16 Validation by onboard measurements
Setting of Fuel Index of the container ship
0
20
40
60
80
100
120
0 20 40 60 80 100 120
NE (%)
Fuel Index (%) Limit Line
NE = NE / NE at MCR
17 Validation by onboard measurements
Calculation: constant M/E rev. mode with Fuel IndexWeather: observed data
Comparison between prediction and measured
ship speedM/E rev.
FOC per day FOC per NM
1 2 3 4 5 6 7 8 9Day
VSW (knot) VESTA SIMS
5knot
1 2 3 4 5 6 7 8 9Day
NE (rpm) VESTA SIMS
10rpm
1 2 3 4 5 6 7 8 9Day
FPD (ton/day) VESTA SIMS
10ton/day
1 2 3 4 5 6 7 8 9
Day
FPM (ton/mile) VESTA SIMS
0.1ton/NM
These are generally good agreement.
18 Validation by onboard measurements
Limit of FI
A prediction model of fuel consumption in actual seas is developed for the purpose of evaluation of that in actual seas.
Conclusions19
Effectiveness of the model is validated through onboard measurements by a container ship under the sea conditions are relatively rough.
The model considers the operating characteristics of M/E; especially Fuel Index.
Thank you for your attentions.