PROPELLERS/SHAFTING '94 SYMPOSIUM

Transcription

1 PROPELLERS/SHAFTING '94 SYMPOSIUM Sponsored by the Ships' Machinery Committee of The Society of Naval Architects and Marine Engineers September 20-21; 1994* Virginia Beach, VA Hosted by The Hampton Roads Section SY-27 Published by The Society of Naval Architects and Marine Engineers 601 Pavonia Avenue Jersey City, NJ UB/TIB Hannover 8! X

2 Contents 1. A Postswirl Propulsor for a Small Vehicle 1-7 Benjamin Y.-H. Chen, Visitor, Carol L. Tseng, Visitor A navel postswirl propulsor designedfor a small vehicle is addressed. The major benefit of this design is the simplicity of the machinery arrangement. The challenge of this design is the low value of Reynolds number which may cause flow separation on the propulsor blade surfaces. Open-water and self-propulsion experimental results show that the performance predictions agree well with the measurements. 2. Applications of Cyclic Pitch Thrusters 1-10 Burke Murray, Visitor, Jim Fraser, Associate Member, Charles Dai, Visitor, Brian Maskew, Member An analysis method for cyclic pitch propellers is outlined. Two examples of possible applications are presented, and a prototype implementation is described 3. Characteristics of Ducted Propellers 1-17 John F. McMahon, Associate Member This paper deals with ductedpropulsors using both blade element and momentum theory. The degree to which the internal flow displays dimensional similarity is discussed 4. Design of Shaft Coupling Bolts 1-12 Steven Shepstone, Associate Member The design of friction, shear, and combined friction and shear bolted couplings are examined. The determination of stresses in shear loaded bolts and the flange surfaces that they contact is emphasized. 5. Lateral Vibration of Shafting 1-21 SNAME Committee M20 on Ship Machinery Vibrations, F. Everett Reed, Life Member and Panel Chairman, Jonathan C. De Hart, Visitor, Moses W. Hirschkowitz, Life Member, Patrick O. Prendergast, Visitor, Steven Stroubakis, Member, Richard T. Woytowich, Member, Ivan Zgaljic, Member This paper is presented as a precursor of a SNAME, M20 Ship Machinery Vibration Guideline for predicting the lateral shaft vibration amplitudes and forces on single and multiple screw ships. Commentsfromthe attendees of the Symposium are sought to make this as useful as possible for the profession. 6. Contrarotating and Tandem CLTPropellers 1-31 Conzalo Perez-Gomez, Member, Juan Gonzalez-Adalid, Visitor The generalization made to the New Momentum Theory with the aim to design CLT propellers working in a velocities field with both axial and tangential components (nozzle propellers, contrarotating propellers, etc.) has allowed the authors to design contrarotating and tandem propellers both with conventional and CLT blades.

3 7. A Three-Dimensional Method for the Inverse Design of Marine Ducted Propeller Bidding l ~ U M. Zangeneh, Visitor, M.E. Roddis, Associate Member A method is presented for the three-dimensional inverse design of single or multi-blade row ducted propulsor blades for a specified blade circulation in axisymmetric inlet shear flow conditions. The method computes the flow through the duct and the propulsor blades simultaneously and is therefore capable of modelling the strong interactions between the blades and the duct. 8. Computational Approximations for Ducted Propellers 1-18 Jennifer B. Brown, Associate Member, David S. Greeley, Associate Member Several computational approximations for the hydrodynamic design and analysis of ducted propellers are developed, with the objective of capturing the important flow physics of ducted units within computer codes suitable for preliminary design use. Applications to both steady and unsteady flow are presented. 9. A Preswirl Stator-Propeller System as a Reliable Energy-Saving Device 1-16 Ki-Sup Kim, Visitor, Moon-Chan Kim, Visitor, Suak-Ho Van, Visitor, Jung-Chun Suh, Visitor, Jin-Tae Lee, Member Procedures for the design, analysis, and model tests of a preswirl stator-propeller system for a 300,000 DWT VLCC are described Five stators were designed and tested using the existing propeller for a 300,000 DWT VLCC in order to verify the effectiveness of the stator-propeller system. Maximum 6.5% decrease in deliveredpower at the design speed (15.5 knots) would be achieved with the designed stator-propeller system. 10. The Flow Adapted Grid (FLAG) Applied to the Analysis of Propeller Tip Flows 1-10 Sangwoo Pyo, Student Member, Spyros A. Kinnas, Associate Member A new panel arrangement, orthogonal at the leading edge and adapted to the resulting flow at the trailing edge, is implemented in a boundary element method for the analysis of propeller tip flows. This panel arrangement is found to improve: (a) the accuracy of the predicted velocity flow field and pressure distribution at the tip region, and (b) the numerical performance of the boundary element method. 11. On the Validation of an Unsteady Lifting Surface Method for Propeller Design Analysis 1-26 Teus van Beek, Visitor, Henri van de Vorst, Visitor The unsteady lifting surface code PUF3A has been evaluated thoroughly for prediction of the propeller performance. Some modifications proved to be necessary. A regression formula is derived for the pitch of the trailing wake behind the blades. After these modifications cavitation performance and pressure pulses have been evaluated for various practical propellers. Finally, the possibility to use PUF3A as a design tool has been investigated. 12. Engineering of Power Boat Propellers /_y<{ William S. Vorus, Life Fellow, Kevin W. Mitchell, Associate Member A computationally-based procedure developed for engineering power boat propellers is presented. Here power boats are being distinguished from ships in that they are considered to be at least partially planing, with their propellers distinguished from ship propellers in that blade cavitation is significantly involved in their propulsive performance. The engineering methodology is applied in an attempt to clarify an active issue in the selection of large sport fishing yacht propellers: larger diameter and lower RPM versus smaller diameter and higher RPM.

4 13. Analysis of Three-Dimensional Boundary-Layer on Propeller Blade 1-11 Akira Oshima, Visitor The three-dimensional boundary-layerflowon a rotating propeller was studied. The differential solution method was used to solve the laminar and turbulent boundary layer equations. The computed velocity components show good agreement with the measured ones. Finally, the influence ofviscosity on propeller performance is discussed. 14. Design of Marine Propellers Using Vortex Theory: Theory and Practice Victor Mishkevich, Member The application of vortex theory to propeller design is discussed New approach is based on improved mathematical model of propeller, including optimization of circulation distribution with restrictions; prescribing of velocity distribution separately for suction and pressure sides of blade; viscosity effect corrections. 15. Propeller Blade Design Including Shear Flow Interaction 1-10 William M. Milewski, Associate Member, David S. Greeley, Associate Member A vortex lattice method lifting surface code and an axisymmetric incompressible Navier-Stokes (RANS) code have been interactively coupled to design wake-adapted propellers. A new body force model has been implemented to represent the axisymmetric component oftheflowconsistently in both models. 16. A Note on the Blade Surface Cavitation Modeling with Viscous Effect 1-8 Charles Dai, Visitor, Joseph Gorski, Visitor This note is to evaluate two analytical models in surface cavitation modeling with the effect of viscosity taken into consideration and to suggest a new approach based on a mixed Lagrangian/Eulerian formulation in the surface cavitation modeling. Comments on the approaches and thoughts of the future cavitation modeling works are also given. 17. Propeller Blade Sections with Improved Cavitation Performance 1-23 Otto Scherer, Member, Robert Stairs, Associate Member A method for the design of propeller blade sections with improved cavitation performance is presented along with sample foil designs and a discussion of their characteristics. Design data is given for selected foil sections with properties superior to conventional NACA sections. 18. Interaction Velocity Field Methodfor Predicting Ship Rudder-Propeller Interaction 1-14 Stephen R. Turnock, Visitor, John F. Wellicome, Visitor, Anthony F. Mollard, Visitor A method for predicting rudder-propeller interaction is presented and compared with experimental measurements. A surface panel program (PALISUPAN) forms the basis of the analysis. The rudder and propeller are modelled separately using an iterative process whereby their respective interaction is accounted for through modifying their inflow velocity field. 19. Practical Experience with Finite Element Analysis of Propeller Blades 1-17 Terry Brockett, Member, and Theodore Brockett, Visitor A general purpose finite element code is applied to estimate the stress, deflection, and fundamental natural frequency of a number of propellers with various loading distributions. Correlation with measured data is achieved with plate and brick elements and with quadrilateral and triangular platforms. Some design issues are explored.

5 20. Hydrodynamic Loads and Dynamic Effects of Cavitation on Ice Class Propellers ut Simulated Ice Blocked Flow 1-19 Daniel Walker, Student Member A series of tests were done in a cavitation tunnel using ice class propellers. The propellers were run in the wake of a nearby simulated ice blockage. Measurements taken included static and dynamic thrust and torque, duct thrust andfluidpressure on the face of the block adjacent to the propeller. The types, patterns, and nature of cavitation were recorded. The effect of cavitation during blockage was a reduction of mean values of thrust and torque and an associated increase in the dynamic oscillation about the mean value. 21. Multi-Component Propulsors for Merchant Ships Design Considerations and Model Test Results 1-13 Eckhard Praefke, Associate Member Three different pairs of counterrotatingpropellers and one stator-rotor-combination have been designed for a fictitious application. LDV measurements have been compared to calculations. The investigation showed that the swirl in the propeller slipstream can be eliminated nearly entirely by the application of counterrotating propellers compared to a single propeller. 22. The Composite Advantage 1-8 Tim Searle, Visitor, John Chudley, Visitor, David Short, Visitor, Chris Hodge, Member For some decades the use offibrereinforced plastic composites have been steadily increasing in the marine industry. The synergy of high modulus, high strength fibres and polymer matrices have significant benefits. Test tanks and vessel trials have been undertaken to evaluate the performance characteristics of a range of composite propellers. Results are presented in this paper. 23. Experimental and Theoretical Analysis of Propeller Shaft Forces of Contra-Rotating Propellers and Correlation with Full Scale Data 1-17 Tetsuji Hoshino, Visitor This paper presents the results of measurements of unsteady propeller shaft forces of a contra-rotating propeller (CRP) operating behind a ship in both model and full scales. Further, unsteady propeller shaft forces were calculated by a lifting surface theory and compared with the results of the measurements. It was found that the calculated propeller shaft forces were in good agreement with the experiments. Further, propeller shaft forces of the CRP measured in full scale coincided well with those predicted from the model experiments.