Download - Global Warming and Impact on ITTC Activities
Global Warming and Impact on ITTC Activities -Energy Saving by Ship Hydro-Aero Dynamics-
National Maritime Research InstituteDirector of Project Teams of Ship Performance Index
Noriyuki Sasaki
Contents
1. CO2 Emission Index - Japanese Proposal -
2. Trend of performance of ships
3. Energy saving devices
4. Simple evaluation method of actual sea performance at initial design phase
5. Conclusions
排出量(百万トン)0 2,000 4,000 6,000 8,000
アメリカ
中国
ロシア
日本
インド
ドイツ
船舶
イギリス
カナダ
韓国
イタリア
メキシコ
フランス
オーストラリア
CO2 Emission from Ships at Operation
•出典)EDMC/エネルギー・経済統計要覧2007年版
・CO2 emission from all ships in the world corresponds to emission from Germany
・CO2 emission from ships tends to increase with growing market of world shipping trade
MEPC57 agreed that the intersessional working group meeting on GHG in Oslo, Norway, should discuss the development of a CO2 design index for new ships.
CO2 Emission Index- Japanese Proposal to IMOANNEX 5
Draft Guidelines on the Method of calculation ofthe new ship design CO2 index
The attained new ship design CO2 index is a measure of ships CO2 efficiency and is:
Wref
NAE
iAEiAEiFAEi
L
kk
NME
iMEiMEiFMEi
M
jj
fVCapacity
PSFCCfPSFCCfindexCOdesignshipNew
××
⎟⎠
⎞⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛+⎟
⎠
⎞⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛
=∑∏∑∏==== 1111
2
CO2 from main engine
CO2 from auxiliary engine
• dead weight
• total volume of cargo tanks
• gross tonnage
design ship speed speed loss
actual speed performance
9 fW is a non-dimensional coefficient indicating the decrease of speed in representative sea conditions of wave height, wave frequency and wind speed (e.g., Beaufort Scale 6), and should be determined as follows:
. 1 It can be determined by conducting the ship-specific simulation of its performance at representative sea conditions. The simulation methodology shall be prescribed in the Guidelines developed by the Organization and the method and outcome for an individual ship shall be verified by the Administration or an organization recognized by the Administration.
2 In case that the simulation is not conducted, fW value should be taken from the “standard fW ” table/curve. A “Standard fW ” table/curve, which is to be contained in the Guidelines, is given by ship type (the same ship as the “baseline” below), and expressed in a function of the parameter of Capacity (e.g., DWT). The “Standard fW ” table/curve is to be determined by conservative approach, i.e., based on the data of actual speed reduction of as many existing ships as possible under the representative sea conditions
CO2 Emission Index- Japanese Proposal to IMO
Similar System to Car FOCR Index
Measure Fuel Oil Consumption Rate under metropolitan driving modes
Trend of CO2 Emission from Ships
• 170 vessels built by Japanese Shipyards• Categorized by ship 8 types (Tanker,Container,PCC,BC,etc)• Fuel oil consumption per traffic volume (FOC/(Capacity*Vs))
are investigated
0
50,000
100,000
150,000
200,000
250,000
300,000
0 100 200 300
DW
Loa
bulk
car
cargo
container
oil
ore
ro-ro
その他
Relation between Loa(m) and DW(ton)
container
tanker
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
0 50,000 100,000 150,000 200,000 250,000 300,000
MC
R(kw
)
DW
bulk
car
cargo
container
oil
ore
ro-ro
その他
Relation between DW(ton) and PMCR (kw)
Relation between DW(ton) and PMCR (kw)
(Container)
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
0 20,000 40,000 60,000 80,000 100,000 120,000
DW(ton)
PMCR (kw)
0
50
100
150
200
250
300
350
1973 1978 1983 1988 1993 1998 2003 2008
100
150
200
250
300
350
400
1973 1978 1983 1988 1993 1998 2003 2008
Tanker
Container
Trend of Ship Length (Lpp) 1975-2005
VLCC
AFRAMAX
PANAMAX
ULCC
13.5
14
14.5
15
15.5
16
16.5
17
1970 1975 1980 1985 1990 1995 2000 2005 2010
Tanker
15
20
25
30
1973 1978 1983 1988 1993 1998 2003 2008
Container
Trend of Ship Speed (kts) 1975-2005
Trend of Design Froude Number 1975-2005
0.150
0.200
0.250
0.300
0.350
1973 1978 1983 1988 1993 1998 2003 2008
0.1
0.125
0.15
0.175
0.2
1970 1975 1980 1985 1990 1995 2000 2005 2010
Tanker
Container
ULCC
0
0.05
0.1
0.15
0.2
1973 1978 1983 1988 1993 1998 2003 2008
Trend of FOC Index of Large Tankers built by Japanese Ship Yards
sec)/(*/mtondaykg
turbine
13.5
14
14.5
15
15.5
16
16.5
17
1970 1975 1980 1985 1990 1995 2000 2005 2010
Tanker
Correction of Vs
Correction of Vs + ship length
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.450
1973 1978 1983 1988 1993 1998 2003 2008
Trend of FOC Index of Large Containers built by Japanese Ship Yards
sec)/(*/mtondaykg
15
20
25
30
1973 1978 1983 1988 1993 1998 2003 2008
Container
Conclusions 1
• Both container ships and tankers, FOC index trend is almost the same except 1995 after
• The different tendency may be brought by the fact that there are no effective energy saving devices for high speed containerships.
• It is also obvious that design ship speed of container ship is not so reliable compared with tanker’s case.
total loss
Energy Loss of a conventional ship
wave resistance
momentum lossviscous lossrotational loss
rudder resistance
viscous resistance
momentum lossviscous lossrotational loss
rudder resistance
Energy Loss of a conventional ship
propulsion loss
Recovered by PropellerThrust deduction
Energy Loss at Ship Navigation
wind resistance
So complicated !
LV-Fin (IHI) 1995DPF (Sumitomo) 1992
Horizontal Fin in front of a propeller
1. Pressure recovery by preventing down flow
2. Induction of bilge vortex to propeller disc
SSD (Universal) SILD (Sumitomo )
Accelerating duct in front of a propeller
1. Pressure recovery by preventing down flow
2. Thrust due to duct
3. Induction of bilge vortex to propeller disc
Scale effect on SILD Performance
-0.01
0.00
0.01
0.02
0.03
0.02 0.04 0.06
Δw
Δ(1
-t)
Small Model
Large Model
SHIP
Scale Effect of energy saving duct
Lpp=2m
Lpp=8m
Lpp=250m
1-2%
4-5%
7%
Improvement of (1-t) may be originated from reduction of section drag of duct due to Rn effect.
(average of 12ships with & 10 ships w/o)
Magnitude of Energy Saving for each device
Recovery of Propeller Energy Loss
Red
uctio
n of
Hul
l/Rud
der r
esis
tanc
e &
Duc
t Thr
ust
2
%
3
% 4
%
5
%
6
%
7
%
8
%
Energy saving device in future
Conclusions 2
•Owing to effective energy saving devices invented by shipyards, FO index of tankers/bulk carriers were much improved in these 20 years.
•Energy saving device in future will have multifunction such as a duct installed in front of a propeller
•CFD will be a good tool to investigate mechanism however, it will be another several years to utilize as a design tool.
•It is very regrettable that there are no effective energy saving devices for containerships which are the most important ships from a global warming view point.
0
4
2 4 Wave height(m)
Spee
d L
oss(
Kno
t
)
◆
Shipyard A▲
Shipyard B○
Shipyard C■
Shipyard D
Calm Sea
Example of Ship Performance at Actual Sea
• Speed loss is not the same even if the ships was designed under the same specification
0
2 Due to ship design
速力変更
ハイブリッド計算手法
Detail of Computation Flow
Tank test
Calculation
Design Index
SHP = constant
Yes
Resistance/Propulsion Test
in still water
Resistance in still water
air resistance
Total resistance
Required thrust
thrust deduction
Propeller loading
Propeller Efficiency
Propeller efficiency
relative rotative efficiency
Hull efficiency
Propulsive Effciency
Delivered Power
Shaft Power
SHP(wave)=SHP
Speed Loss
Ship motion in regular wave
Resistance in regular wave spectrum
Resist. in short crest irregular wave
Effective horse power
M/E performance
Fuel Oil Consumption
Ship Speed =const
BFSpeed Loss)
Iterated Process
Linearization 2
Simplified Method
波浪中抵抗増加計算
船体斜行・あて舵計算
波浪中自航計算
波浪中馬力計算
波浪中船速低下計算
主機燃料消費
理論計算の補正
Cal. of Resistance in Waves
Effect of Wind Resistance
Propulsive Efficiency
Required Power in Waves
Speed Loss due to Waves
Fuel Oil Consumption
Correction based on Model Test
Design Index of Ship Performance
Linearization 1
hull Form
J
KT
KQ
POWC
Simplified Method can be used at initial design phase where we hardly get the detailed information for the designed vessel.
平水中模型試験
正面規則波抵抗試験
Resistance Test
Resistance Test in Regular WaveEmpirical Formula
)1(21* 8.0
22
1 Ba FnCBBfcpgCRaw += ζρ
Simplified Method by EXCEL Calculation
Head Wind
13.50
14.00
14.50
15.00
15.50
16.00
16.50
1 2 3 4 5 6 7 8
Beaufort Sca le
Ship
Speed(k
ts)
Voyage Data
CAL by Hope
Simplified Method of Added Resistancein Wavekind of Ship ContainerCapacity 6500 TEULpp 300 mB 40 mD 24 md 14 mCb 0.65Disp 111930 tonCp 0.658LCB 0.59 %Lpp
Af 1548 m**2
Dp 8.8 m
1-t 0.831-w 0.73Vs 26.0 24.7 23.4 ktsEHP 37,735 30,926 26,064 KWBHP 51,786 41,981 35,195 KWCal of Ship Speed in actual seaVs 26.0 24.7 23.4Ro 287790 248268 220864Cp 0.658δCp 0.0285Cpf 0.644Bfcp2 0.034Fnb 0.676 0.642 0.608C1 1.00C2 31.28Raw(regular) 37210 35776 34328Raw 18605 17888 17164C0 0.60Raa 28370 27406 26442To 345403 297970 265080To+δT 401782 352331 317415Ct 1.140 1.090 1.080Ct' 1.326 1.289 1.293ηo'/ηo 0.975 0.973 0.971 929.8008BHP' 61762 51004 43388δVs -1.19Vs (result) 24.8δP'/P 19% 21% 23%fw 0.954
Power Curves(calm)
Input items
(1) Principal dimensions of ship
(2) Power curves (3 points)
(3) Self propulsion factors
(4) Frontal area of superstructure
Effect of measurement position on wind velocity
Conclusion
• Design Index of CO2 emission for individual ship was proposed to IMO and this proposal will be accepted
• Simulation or prediction tool for CO2 emission at actual sea is very important and the tool should be simple and robust.
• New idea of energy saving device for high speed ship such as containership is burning issue.
• Energy saving devices for slow speed vessels such tankers should be deeply investigated. Especially, scale effect and performance in wave are important.
• Resistance increment due to wind at navigation is not clear and full scale measurement will help us to understand.