Propulsion efficiency improvement through                    CFD               Vessel Efficiency                    Simon ...
Overview of presentationCJR Propulsion and initial propeller design toolsAnalysis of a hull using CFDOptimisation of prope...
CJR Propulsion Ltd. – Company backgroundCJR propulsion is a leading propeller design and manufacture companyAlso manufactu...
Initial Propeller performance calculationsHistorically, propeller design was based on propeller series data and experience...
Limitations of this methodNo method for determining the realistic inflow to the propeller plane – a uniform       flow is ...
Knowledge transfer partnershipIn order to overcome these limitations, CJR decided to seek assistance from the         Univ...
CFD analysis of a planing hullCFD mesh of the hull and     appendages.                           Free surface showing     ...
Analysing the flow into the propeller     CFD mesh of the hull and appendages.
CFD analysis of a planing hullStreamlines of the flow        under the hull                          Cross flow velocities...
CFD Study - Results
Case Study: P-bracket designThe aim is to demonstrate how the P-bracket design alters the flow into thepropeller. This is ...
Preliminary CFD Study – Propeller plane                    Velocity in the x direction (forward velocity)            26º P...
Propeller DesignFour propellers are analysed once the wake predictions are completedPropellers are analysed in the followi...
Propeller Design – Thrust predictions
Propeller Design – Torque predictions                15                                                  5x42.5x49        ...
Propeller Design –prediction of pressure pulses on hull                           30                                      ...
Propeller Design –prediction of cavitationCavitation erosion
Case study conclusionsA design procedure for improving stern gear has been presentedThe initial results suggest that there...
Trim and resistance analysis                           Variation of drag with displacement for                            ...
Propeller raceCFD simulation of the propeller and entire hull                                                  Axial veloc...
Rudder designTwo rudder designs are analysedRudder A is a wedge rudder with a blended stock, and toed in by 2.5 °Rudder B ...
Rudder designPressure on rudder surfaces at 0 degrees pitch.       Rudders at 35 degrees pitch, with streamlines.
CFD Spray analysisCFD mesh of the hull is refined at the free surface.
CFD Spray analysis                          Analysis of the free surface flow.•   Evaluate the spray of a planing craft in...
Recent success storiesThe propeller design of the following yachts has used all or some of themethod presented:Manufacture...
ConclusionsThe collaborative research and development project has been a hugebenefit to both the University of Southampton...
CFD consultancy work by CJR
CFD consultancy work by CJRPicture courtesy of ICAP leopard
Future workImprove the propeller momentum source in the CFD to include variationsin the propeller thrust and torque as eac...
Future work
Questions   ?   Simon LewisSimon@cjrprop.com   07868742997
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Vessel efficiency competition case study - Simon Lewis computational flow dynamics

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Propulsion efficiency improvement through CFD

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  • This was how we ran the project, and how we gained from the project. There is a lot to be gained after the project, as now CJR is doing consultancy work using CFD eg fishing trawlers, Dixon yacht design, and military craft, catamaran, and high performace sailing boat
  • This was how we ran the project, and how we gained from the project. There is a lot to be gained after the project, as now CJR is doing consultancy work using CFD eg fishing trawlers, Dixon yacht design, and military craft, catamaran, and high performace sailing boat
  • This was how we ran the project, and how we gained from the project. There is a lot to be gained after the project, as now CJR is doing consultancy work using CFD eg fishing trawlers, Dixon yacht design, and military craft, catamaran, and high performace sailing boat
  • Cjr with the university of southamptonis planning to appy for a grant from these funds and we will be looking for partners with similar interests and aspirations.
  • Vessel efficiency competition case study - Simon Lewis computational flow dynamics

    1. 1. Propulsion efficiency improvement through CFD Vessel Efficiency Simon Lewis Tuesday 27th November2012
    2. 2. Overview of presentationCJR Propulsion and initial propeller design toolsAnalysis of a hull using CFDOptimisation of propeller designP-bracket analysis and design using CFD – A case studySpray analysisRudder designRecent successesFuture work
    3. 3. CJR Propulsion Ltd. – Company backgroundCJR propulsion is a leading propeller design and manufacture companyAlso manufacture other underwater hull appendages such as rudders, P-bracketsand propeller shafts.World leader in advanced manufacturing methods – One of the only companiesin Europe with the capability to machine propellers with a 5-axis CNC millingmachine
    4. 4. Initial Propeller performance calculationsHistorically, propeller design was based on propeller series data and experienceA lifting surface model and ship resistance prediction program was introduced tothe design procedure in 2007. This allows:• Accurate hull resistance prediction• Accurate propeller performance prediction• Cavitation on the propeller blades to be predicted (subject to accurate inflow data)• Pressure field around the hull as well as pressure pulses on the hull are calculated – these are responsible for propeller noise and vibration (subject to accurate inflow data)
    5. 5. Limitations of this methodNo method for determining the realistic inflow to the propeller plane – a uniform flow is assumed, although this is not the case as the flow has to travel passed the shaft and shaft bracket before reaching the propeller.Cavitation and propeller pulses cannot be accurately predicted if the inflow conditions are not known.In order to improve the rudder design, the flow entering the rudder region must be known.No method of determining the effect of the shaft, shaft bracket and other appendages on the propeller performance
    6. 6. Knowledge transfer partnershipIn order to overcome these limitations, CJR decided to seek assistance from the University of Southampton.The two organisations won funding for a 2 year knowledge transfer partnership (KTP) funded by the TSBThe aim of the KTP was to improve sterngear design through the use of advanced computational fluid dynamics (CFD).
    7. 7. CFD analysis of a planing hullCFD mesh of the hull and appendages. Free surface showing hull wake.
    8. 8. Analysing the flow into the propeller CFD mesh of the hull and appendages.
    9. 9. CFD analysis of a planing hullStreamlines of the flow under the hull Cross flow velocities in the propeller plane
    10. 10. CFD Study - Results
    11. 11. Case Study: P-bracket designThe aim is to demonstrate how the P-bracket design alters the flow into thepropeller. This is achieved by• Simulating the flow around a hull using CFD to gain a better understanding of the flow into the propeller.• Altering the P-bracket design and analysing the effects: -8º 15º 26º
    12. 12. Preliminary CFD Study – Propeller plane Velocity in the x direction (forward velocity) 26º P-bracket -8º 15º
    13. 13. Propeller DesignFour propellers are analysed once the wake predictions are completedPropellers are analysed in the following flow regimes:• Uniform wake• CFD predicted wake with -8º P-bracket• Trials data with -8º P-bracket• CFD predicted wake with 15º P-bracket• CFD predicted wake with 26º P-bracketPropellers are analysed using in-house code and a vortex lattice method
    14. 14. Propeller Design – Thrust predictions
    15. 15. Propeller Design – Torque predictions 15 5x42.5x49 5x42.5x50.5 14.5 5x42.5x50.5 MOD 14 5x42.5x50.5 REVTorque (kNm) 13.5 13 12.5 5x42.5x50.5 REV 12 5x42.5x50.5 MOD 11.5 5x42.5x50.5 Uniform -8 5x42.5x49 -8 trials 15 26
    16. 16. Propeller Design –prediction of pressure pulses on hull 30 5x42.5x49 25 5x42.5x50.5 Pressure pulses (kPa) 20 5x42.5x50.5 MOD 15 5x42.5x50.5 REV 10 5x42.5x50.5 REV 5 5x42.5x50.5 MOD 0 5x42.5x50.5 Uniform -8 5x42.5x49 -8 trials 15 26
    17. 17. Propeller Design –prediction of cavitationCavitation erosion
    18. 18. Case study conclusionsA design procedure for improving stern gear has been presentedThe initial results suggest that there are significant savings to be made interms of stern gear drag and propeller noise and vibration.P-bracket design affects the propeller performance and optimisation of thiscomponent provides• A cleaner flow into the propeller.• Significant reduction in the predicted pressure pulses on the hull.• Increase in propeller thrust and torque.Cavitation predictions are comparable with reality when the CFD wake is used
    19. 19. Trim and resistance analysis Variation of drag with displacement for three different trim angles.• Prediction of drag and running trim.• Calculation of optimum position of the centre of gravity.• Sensitivity studies can be undertaken to evaluate the effect of changing the hull parameters including displacement.
    20. 20. Propeller raceCFD simulation of the propeller and entire hull Axial velocity Vertical velocity
    21. 21. Rudder designTwo rudder designs are analysedRudder A is a wedge rudder with a blended stock, and toed in by 2.5 °Rudder B is a wedge rudder without a blended stock and has no toe in angle
    22. 22. Rudder designPressure on rudder surfaces at 0 degrees pitch. Rudders at 35 degrees pitch, with streamlines.
    23. 23. CFD Spray analysisCFD mesh of the hull is refined at the free surface.
    24. 24. CFD Spray analysis Analysis of the free surface flow.• Evaluate the spray of a planing craft in calm water.• Effect of changes in the hull design (such as spray rail dimensions) on the spray.
    25. 25. Recent success storiesThe propeller design of the following yachts has used all or some of themethod presented:Manufacturer Yacht Required speed (kts) Achieved speed (kts)Alnmaritec 16m Pilot boat 25 27.6Alnmaritec 19m patrol boat 36 37.6Holyhead Marine 16m Pilot boat 25 28Mustang Marine Humber pilot boat 25.7 (previous props) >27Seaward Marine Tenerife pilot boat 21 23.5Seaward Marine Guernsey ambulance boat 25 26.7
    26. 26. ConclusionsThe collaborative research and development project has been a hugebenefit to both the University of Southampton and CJR Propulsion: CJR made extensive use of the resources at the university such as the Iridis 3 computer cluster and the in house CFD expertise gained from years of research. The university has improved links to industry, and gained insight and knowledge from the research carried out during the project.The improved lines of communication between the two has allowedfurther collaboration in the area of composite propellers which included astudent at the university working on a summer placement at CJR.CJR now offer a CFD consultancy service
    27. 27. CFD consultancy work by CJR
    28. 28. CFD consultancy work by CJRPicture courtesy of ICAP leopard
    29. 29. Future workImprove the propeller momentum source in the CFD to include variationsin the propeller thrust and torque as each blade sweeps around the diskFurther sea trials are planned with a variable rudder toe in angle in orderto fully quantify the effect of this against speed and turning performanceIncluding hull motion in the CFD to allow the hull to find its own heaveand trim, and eliminate the need to carry out a matrix of nine simulationsInclude the full propeller model in the CFD simulation to further enhancepredictions.
    30. 30. Future work
    31. 31. Questions ? Simon LewisSimon@cjrprop.com 07868742997

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