Analysis of the suction wing propeller

as auxiliary wind propulsion

for cargo ships

Philippe PALLU DE LA BARRIÈREJérôme VÉDRENNE

NATURAL PROPULSION SEMINAR – DELFT 2015

CRAIN

- Founded in 1984

- Strong background in hydrodynamics, aerodynamics, naval architecture and wind propulsion

- Zero-emission electric passenger ferries (10 ferries, 2 millions passengers / year, no emission), hybrid ferries

- Reduction of emission for ships

- Offshore racing yachts, America’s Cup,…

- Study of fishing ship with sail

Natural Propulsion Seminar – Delft 2015 2/19

Study background

FP7 ULYSSES project 2011-2013

- Slow steaming for tankers and bulkers

CRAIN R&D program 2010-2014

- Performance prediction tools for ship using auxiliary wind propulsion

- Weather routing method with fixed travel time

- Aerodynamic analysis of various wind propulsion concepts

- Development of a wind propulsion system based on the suction wing concept

Natural Propulsion Seminar – Delft 2015 3/19

4/19

Aerodynamic efficiency

Greater aerodynamic force / unit area reduced device size need less room on deck

Higher lift to drag ratio more thrust, more efficient and more versatile more efficient for fast ship or upwind trips To increase aerodynamic force par unit area :- increase Vapp through dynamic and altitude (kite)- increase Ca by energy intake(rotor, suction wing, blowing)

Better lift to drag ratio :- increase effective height (stability and structural issues)- reduced section drag (thick section, suction airfoil)

Vapp : ship apparent wind speedS,CA : Propulsion Power coefficient

Natural Propulsion Seminar – Delft 2015

5/19

Historical background

-Suction wing concept : extensively tested for aeronautics since the 40’s and 50’s

Natural Propulsion Seminar – Delft 2015

-Adapted to marine propulsion by Malavard and Charrier for Cousteau’s Alcyone in 1984 (still sailing)

6/19

Suction wing concept

Principle

- Energy consumption

- High efficiency

- Powerful (Ca = 7)

- High lift to drag ratio

- Very thick section

- Boundary layer suction Prevent flow separation

Properties

Natural Propulsion Seminar – Delft 2015

7/19

Suction wing

Natural Propulsion Seminar – Delft 2015

8/19

Comparison with rotor

Natural Propulsion Seminar – Delft 2015

Suction wing Rotor

Principle Boundary layer suction Magnus effect

Lift magnitude High High

Size Small Small

Consumption Moderate High

Lift to drag ratio High Moderate

Areas for improvement High No

Flexibility High Low

Safety Slowly moving partLarge high speed

rotating part

9/19

Potential improvements

Natural Propulsion Seminar – Delft 2015

- External aerodynamics

- head loss- internal duct shape- fan efficiency- suction inlet shape and position

- section shape- camber flap shape and position- outlet shape

- Internal aerodynamics

- Adaptation to ship operational profile

- lift to drag ratio depending on ship speed - power- size

10/19

Technical means

Natural Propulsion Seminar – Delft 2015

Suction wing can be improved and adapted but this requires complex aerodynamic developments

- Intensive CFD calculation have been carried out for various configurations and setup

- Wind tunnel campaigns have confirmed the theoretical potential of the suction wing concept and validated progress achieved in the design

- A prototype with a on shore permanent setup is planned for testing in a natural environment, collecting operational data, checking reliability and automation.

11/19

Wind propulsion criteria

Natural Propulsion Seminar – Delft 2015

12/19

Auxiliary wind propulsion

Performance prediction tool chain

- Aerodynamic models for various wind propulsion systems

- Ship performance model including auxiliary wind propulsion

- Weather routing for commercial ships (fixed trip time, optimal route calculation for minimal consumption)

- Analysis of energy performances taken on operating route

Natural Propulsion Seminar – Delft 2015

13/19

Case study

- 50 000 DWT Tanker, LOA 183 m- Service speed : 15 knots

Course- Transatlantic : 3600 nautical miles- Fixed trip time- Mean speed 8, 10 et 12 knots

Ship

Natural Propulsion Seminar – Delft 2015

Auxiliary propulsion : 4 x suction wings

- Transatlantic : 3600 nautical miles- Fixed trip time- Mean speed 8, 10 et 12 knots

- Height : 24 m- Side area : 4 x 96 m2

14/19

Case study

Fossil energy saving due to wind propulsion usage

Average speed (kt) 8 10 12

Direct route 20 % 14 % 7 %

Optimized route(*) 33 % 26 % 12 %

Average speed (kt) 8 10 12

Without wind propulsion, direct route 8,6 t/d 14,9 t/d 23,3 t/d

Using wind propulsion, optimized route (*) 5,7 t/d 11,1 t/d 20,0 t/d

Fuel saving 2,9 t/d 3,6 t/d 3,3 t/d

(*) Average saving based on 144 return trip from 2000 to 2011

Fuel consumption

Natural Propulsion Seminar – Delft 2015

15/19

Case study

Suction wing financial balance

Natural Propulsion Seminar – Delft 2015

16/19

King size perspectives

Natural Propulsion Seminar – Delft 2015

- VLCC tanker 300 000 DWT

- LOA 330 m, Beam 60 m, Depth 30 m

- Suction wing x4

- 36 m height x 6 m wide

- Sail area : 864 m2

- Potential fuel oil saving 9 t/d

- Scalability : no technological issue

17/19

Current projects

- Based on suction wing concept- Height : 7.5 m- Area : 9 m2

- First test in 2016, on shore permanent setup

- Sea trials, fitted on a fishing ship, in 2017

Wind propeller prototype

Natural Propulsion Seminar – Delft 2015

18/19

Conclusions

- Wind propeller based on the suction wing concept allows reducing significantly ship consumption and GHG emissions

- Suction wing concept is efficient, addresses all ship constraints and can be largely improved in the future

- Short term profitability is planned for a tanker fitted with suction airfoils operating across the Atlantic

- The tool chain that we have shown can assess energetic, environmental and economical performances of a ship depending on its exploitation

- Weather routing optimization is required to take advantage of wind propulsion potential

Natural Propulsion Seminar – Delft 2015

19/19

Thank you for your attention

Natural Propulsion Seminar – Delft 2015