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and then to eheck the strength ofthe propeller design. The detailed steps ofCFD and FEA for a propeller design arc listed in Chapter 3. 2.6 Review of Propeller Fabrication Following the design validation through CAE, a real prototype part is nceded to be fabricated for testing. With the development ofcomputer aided engineering (CAE) softwarc, some software applications are available for propeller simulation, which can predict the results ofa propeller test and be a convenient way for engineers to speed up the design ofthe final pmpcller. Because simulation does not reflect all the aspects ofthe real world accurately, simulation models arc designed and used with the goal of approximating the testing process, but, can't completely replace the testing process. Physical prototype testing is used to increase to an acceptable level the confidence that the simulation results are correct for the real component [29]. For this reason, propellers need to be fabricated for testing after the simulation. 111ere are generally three methods of propeller fabrication: Casting and Computed Numerically Control (CNC) machining technology are the traditional methods. In the latc 1980s, rapid prototyping (RP) was introduced and by thc late 90's it was used as a low cost and fast process for physical prototype fabrication. 2.6.1 Traditional Fabrication Processes Casting is a manufacturing process which involves pouring liquid material into a mould designed with thc desired shape, and then allowing to solidify. The solidified component 32
known as a casting, is usually ejected or broken out ofthe mould and then put through a finishing process [30]. Figure II is the flow chart ofa standard casting process. Build mould Pour liquid material Solidification Take out the part Fi!,'Ure II: Flow Chart of Casting Processes Finishing machining As a traditional manufacturing process, casting consists of several major steps from inception to completion ofa product. These are: demand for a casting of specific shape and size; production ofdrawings, patterns or prototypes; the application ofsimple experienced-based rules to ensure good molten metal behavior. All these require some engineering to produce a good casting and will often take several attempts before a satisfactory result is obtained upon the development of a new product [31]. Due to these requirements ofcasting, cost and process time are major problems for building test prototypes. CNC machining technology is also commonly used to produce propellers. In the CNC process, CAD files provide the input for computer aided manufacturing programs, which are commonly used to extract computer filc for a component and to extract the commands that are loaded into the CNC machines for production. CNC process can be significantly faster than casting but they are still fairly time consuming and expensive. For example, the time to produce a propeller with 200mm diameter usually takes more than two weeks, and the cost is around $2000, ifthe material is brass (Technical Service, <strong>Memorial</strong> <strong>University</strong>). Compared with CNC technology, casting will take a longer time and cost much morc, because several processing technologies will be used for finishing machining. However, casting has two advantages: casting can save J3
Page 4: A Rapid Development Process for Mar
Page 7 and 8: Table of Contents Abstract ... Ackn
Page 9: List ofTables Table I: Required Inp
Page 12 and 13: Figure 46: Surface Dynamic Pressure
Page 14 and 15: a long time to analyze, draw, fabri
Page 16 and 17: Simulation work is now commonly don
Page 18 and 19: Early theoretical analysis applied
Page 20 and 21: ------------------------- provides
Page 22 and 23: As can be secn in Table I, the lift
Page 24 and 25: propeller geometry has to be entere
Page 27: avoid cavitation; however, it decre
Page 31: l" ........... ,... __ .... :l ,,_
Page 34: Table 2: Advantages and Disadvantag
Page 41 and 42: trend for many companies to reduce
Page 43: fluxes through a particular control
Page 47 and 48: Table 3: Prototyping Technology Mat
Page 49: quite accuratc for a testing level.
Page 54 and 55: For given values ofJ, Fn, Rn, En, t
Page 56: propeller geometry for impon into t
Page 59 and 60: Using OpenPVL_SW I a propeller desi
Page 64: o ...n".... 'Co 'OJ • • • DC)
Page 72 and 73: 3.3 Simulations using CosmosFloWork
Page 75 and 76: simulation domain are set to 6m and
Page 79: CosmosWorks can be used to check th
Page 82: Figure 33: Dynamic Pressure Distrib
Page 88: Chapter 4 Case Study: Simulation of
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The plots of RPM and thrust from ou
Page 96 and 97:
Figure 46: Surface Dynamic Pressure
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Figure 48: Deflection ofthe AUV Pro
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In this simulation, two nose cones
Page 110 and 111:
Chapter 6 Propeller Fabrication by
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Figure 60: Stratasys rDM 2000 After
Page 115 and 116:
Material options for Stratasys Fusi
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Chapter 7 Conclusions and Future Wo
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References III Burtner, E., 1953, "
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[20] D'Epagnier, P.K., 2005, "A Com
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Appendix 1\: The Part ofOpcnPVL_SW
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Create all of the function commands
Page 131:
Appendix B: SolidWorks Macro lor th
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'create loft swModcl.ClearSelcction
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