Global Warming and Impact on ITTC Activities - Energy Saving by Ship Hydro-Aero Dynamics- National Maritime Research Institute Director of Project Teams of Ship Performance Index Noriyuki Sasaki
Contents 1. CO 2 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
CO2 Emission from Ships at Operation ・ 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 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 • 出典） EDMC ／エネルギー・経済統計要覧 2007 年版 オーストラリア 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.
CO 2 Emission Index- Japanese Proposal to IMO ANNEX 5 Draft Guidelines on the Method of calculation of the new ship design CO 2 index The attained new ship design CO 2 index is a measure of ships CO 2 efficiency and is: CO2 from CO2 from auxiliary main engine engine ⎛ ⎞ ⎛ ⎞ ⎛ ⎞ ⎛ ⎞ M NME L NAE ∑ ∑ ∏ ∏ ⎜ ⎟ ⎜ ⎟ + ⎜ ⎟ ⎜ ⎟ f C SFC P ⎜ f ⎟ C SFC P ⎜ ⎟ j FMEi MEi MEi k FAEi AEi AEi ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ = = = = = j 1 i 1 k 1 i 1 New ship design CO index × × 2 Capacity V f ref W • dead weight design ship speed speed loss • total volume of cargo tanks • gross tonnage actual speed performance
CO 2 Emission Index- Japanese Proposal to IMO 9 f W 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, f W value should be taken from the “standard f W ” table/curve. A “Standard f W ” 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 f W ” 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
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
Relation between Loa(m) and DW(ton) 300,000 250,000 bulk 200,000 car tanker cargo 150,000 DW container oil 100,000 ore container ro-ro 50,000 その他 0 0 100 200 300 Loa
Relation between DW(ton) and P MCR (kw) 70,000 60,000 bulk 50,000 car 40,000 cargo MCR(kw) container 30,000 oil ore 20,000 ro-ro 10,000 その他 0 0 50,000 100,000 150,000 200,000 250,000 300,000 DW
Relation between DW(ton) and P MCR (kw) (Container) 70,000 60,000 50,000 P MCR (kw) 40,000 30,000 20,000 10,000 DW(ton) 0 0 20,000 40,000 60,000 80,000 100,000 120,000
Trend of Ship Length (Lpp) 1975-2005 400 ULCC VLCC 350 300 AFRAMAX Tanker 250 PANAMAX 200 150 100 350 1973 1978 1983 1988 1993 1998 2003 2008 300 250 200 Container 150 100 50 0 1973 1978 1983 1988 1993 1998 2003 2008
Trend of Ship Speed (kts) 1975-2005 17 16.5 16 15.5 15 Tanker 14.5 14 30 13.5 1970 1975 1980 1985 1990 1995 2000 2005 2010 25 20 Container 15 1973 1978 1983 1988 1993 1998 2003 2008
Trend of Design Froude Number 1975-2005 0.2 Tanker 0.175 0.15 0.125 ULCC 0.350 0.1 1970 1975 1980 1985 1990 1995 2000 2005 2010 0.300 Container 0.250 0.200 0.150 1973 1978 1983 1988 1993 1998 2003 2008
Trend of FOC Index of Large Tankers built by Japanese Ship Yards kg / day 17 ton * ( m / sec) 0.2 16.5 16 15.5 15 Tanker 14.5 0.15 14 13.5 1970 1975 1980 1985 1990 1995 2000 2005 2010 0.1 Correction of Vs + ship length 0.05 Correction of Vs turbine 0 1973 1978 1983 1988 1993 1998 2003 2008
Trend of FOC Index of Large Containers built by Japanese Ship Yards kg / day ton * ( m / sec) 30 0.450 25 0.400 20 0.350 Container 15 1973 1978 1983 1988 1993 1998 2003 2008 0.300 0.250 0.200 0.150 0.100 1973 1978 1983 1988 1993 1998 2003 2008
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.
Energy Loss at Ship Navigation Energy Loss of a conventional ship Energy Loss of a conventional ship So complicated ! rudder resistance rudder resistance rotational loss rotational loss viscous loss viscous loss propulsion loss momentum loss momentum loss Thrust deduction total Recovered by Propeller loss viscous resistance wind resistance wave resistance
Horizontal Fin in front of a propeller LV- LV-Fin (IH in (IHI) 1995 ) 1995 DPF (Sum F (Sumitomo) 1992 mo) 1992 1. Pressure recovery by preventing down flow 2. Induction of bilge vortex to propeller disc
Accelerating duct in front of a propeller SILD SILD (Su (Sumitom mitomo ) o ) SSD SSD ( (Universal al) 1. Pressure recovery by preventing down flow 2. Thrust due to duct 3. Induction of bilge vortex to propeller disc
Scale Effect of energy saving duct 0.03 SHIP Lpp=250m 7% (average of 12ships with & 10 ships w/o) 0.02 Large Model Lpp=8m 4-5% Δ(1-t) 0.01 Small Model 0.00 Lpp=2m 1-2% -0.01 0.02 0.04 0.06 Δw Improvement of (1-t) may be Scale effect on SILD Performance originated from reduction of section drag of duct due to Rn effect.
Magnitude of Energy Saving for each device Reduction of Hull/Rudder resistance Energy saving device in future ８ ％ ７ & Duct Thrust ％ ６ ％ ３ ５ ％ ％ ４ ％ ２ ％ Recovery of Propeller Energy Loss
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.
Example of Ship Performance at Actual Sea • Speed loss is not the same even if the ships was designed under the same specification Calm Sea Wave height （ｍ） 0 2 4 0 ） Speed Loss(Knot 2 Due to ship design ◆ Shipyard A 4 ▲ Shipyard B ○ Shipyard C ■ Shipyard D
ハイブリッド計算手法 Detail of Computation Flow Resistance/Propulsion Test in still water Ship motion in regular wave Resistance in regular wave spectrum Resistance in still water air resistance Resist. in short crest irregular wave Total resistance Effective horse power thrust deduction Tank test Required thrust Calculation Propeller loading Design Index 速力変更 Propeller efficiency Propeller Efficiency relative rotative efficiency Hull efficiency Propulsive Effciency Delivered Power Ship Speed =const Iterated Process M/E Fuel Oil Consumption Shaft Power performance Speed Loss) SHP = constant BF SHP(wave)＝SHP Yes Speed Loss
Simplified Method Resistance Test 平水中模型試験 hull Form Empirical Formula Linearization 1 Resistance Test in Regular Wave 正面規則波抵抗試験 波浪中抵抗増加計算 Cal. of Resistance in Waves 1 = ρ + 0 . 8 ζ 2 Correction based on Model Test 理論計算の補正 Raw C * g BBfcp ( 1 C Fn ) a 1 2 B 2 POWC Effect of Wind Resistance 船体斜行・あて舵計算 K T Linearization 2 波浪中自航計算 Propulsive Efficiency K Q Fuel Oil Consumption Required Power in Waves 主機燃料消費 波浪中馬力計算 J Design Index of Ship Performance Speed Loss due to Waves 波浪中船速低下計算 Simplified Method can be used at initial design phase where we hardly get the detailed information for the designed vessel.
Recommend
More recommend
