Analysis of the suction wing propeller as auxiliary wind propulsion for cargo ships Philippe PALLU DE LA BARRIÈRE Jérôme VÉDRENNE NATURAL PROPULSION SEMINAR – DELFT 2015

CRAIN - Founded in 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 /19

Study background FP7 ULYSSES project Slow steaming for tankers and bulkers CRAIN R&D program 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 /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 speed S,C A : 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 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 wingRotor PrincipleBoundary layer suctionMagnus effect Lift magnitudeHigh SizeSmall ConsumptionModerateHigh Lift to drag ratioHighModerate Areas for improvementHighNo FlexibilityHighLow SafetySlowly moving part Large high speed rotating part

9/19 Potential improvements Natural Propulsion Seminar – Delft 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 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)81012 Direct route20 %14 %7 % Optimized route(*)33 %26 %12 % Average speed (kt)81012 Without wind propulsion, direct route8,6 t/d14,9 t/d23,3 t/d Using wind propulsion, optimized route (*)5,7 t/d11,1 t/d20,0 t/d Fuel saving2,9 t/d3,6 t/d3,3 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 VLCC tanker DWT - LOA 330 m, Beam 60 m, Depth 30 m - Suction wing x m height x 6 m wide - Sail area : 864 m 2 - 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